The Light Skin Allele of SLC24A5 in South Asians and Europeans Shares Identity by Descent
Chandana Basu Mallick equal contributor mail, Florin Mircea Iliescu equal contributor, Märt Möls, Sarah Hill, Rakesh Tamang, Gyaneshwer Chaubey, Rie Goto, Simon Y. W. Ho, Irene Gallego Romero,Federica Crivellaro, Georgi Hudjashov, Niraj Rai,Mait Metspalu, [ ... ], Toomas Kivisild
Abstract
Skin pigmentation is one of the most variable phenotypic traits in humans. A non-synonymous substitution [rs1426654] in the third exon of SLC24A5 accounts for lighter skin in Europeans but not in East Asians. A previous genome-wide association study carried out in a heterogeneous sample of UK immigrants of South Asian descent suggested that this gene also contributes significantly to skin pigmentation variation among South Asians. In the present study, we have quantitatively assessed skin pigmentation for a largely homogeneous cohort of 1228 individuals from the Southern region of the Indian subcontinent. Our data confirm significant association of rs1426654 SNP with skin pigmentation, explaining about 27% of total phenotypic variation in the cohort studied. Our extensive survey of the polymorphism in 1573 individuals from 54 ethnic populations across the Indian subcontinent reveals wide presence of the derived-A allele, although the frequencies vary substantially among populations. We also show that the geospatial pattern of this allele is complex, but most importantly, reflects strong influence of language, geography and demographic history of the populations. Sequencing 11.74 kb of SLC24A5 in 95 individuals worldwide reveals that the rs1426654-A alleles in South Asian and West Eurasian populations are monophyletic and occur on the background of a common haplotype that is characterized by low genetic diversity. We date the coalescence of the light skin associated allele at 22–28 KYA. Both our sequence and genome-wide genotype data confirm that this gene has been a target for positive selection among Europeans. However, the latter also shows additional evidence of selection in populations of the Middle East, Central Asia, Pakistan and North India but not in South India.
Author Summary
Human skin color is one of the most visible aspects of human diversity. The genetic basis of pigmentation in Europeans has been understood to some extent, but our knowledge about South Asians has been restricted to a handful of studies. It has been suggested that a single nucleotide difference in SLC24A5 accounts for 25–38% European-African pigmentation differences and correlates with lighter skin. This genetic variant has also been associated with skin color variation among South Asians living in the UK. Here, we report a study based on a homogenous cohort of South India. Our results confirm that SLC24A5 plays a key role in pigmentation diversity of South Asians. Country-wide screening of the variant reveals that the light skin associated allele is widespread in the Indian subcontinent and its complex patterning is shaped by a combination of processes involving selection and demographic history of the populations. By studying the variation of SLC24A5 sequences among a diverse set of individuals, we show that the light skin associated allele in South Asians is identical by descent to that found in Europeans. Our study also provides new insights into positive selection acting on the gene and the evolutionary history of light skin in humans.
Introduction
Human skin color varies widely among and within populations and is a classic example of adaptive evolution. Skin pigmentation in humans is largely determined by the quantity and distribution of the pigment melanin, which is packed in melanosomes and then transferred from melanocytes [melanin-forming cells] to the surrounding epidermal keratinocytes [1]. Human melanin is primarily composed of two distinct polymers: eumelanin [brown/black] and pheomelanin [yellow/red], which differ in their physical properties and chemical composition [2]. In addition to the amount and type of melanin, other factors such as the size, shape, number, and cellular distribution of melanosomes also contribute to the variation in skin color [3]. Comparative studies of model organisms, pigmentation disorders and genome-wide studies have played a key role in the identification of human pigmentation genes [4]–[7]. A total of 378 candidate loci, including 171 cloned genes, are currently recorded in the Color Genes database [http://www.espcr.org/micemut/], yet only a few of them have been confirmed to have potentially function-altering polymorphisms in humans.
A significant correlation between skin color and ultraviolet radiation [UVR] levels observed at the global scale suggests that natural selection plays an important role in determining the distribution of this phenotypic trait [8]. The evolution of dark skin at low latitudes has been mainly accredited to the requirement of photo-protection against UVR which causes sunburn and skin cancer, whereas the evolution of light skin has been most commonly associated with vitamin D deficiency [9], [10]. It has been proposed that as humans started to colonize higher latitudes, where UVR levels were lower, dark skin could not absorb sufficient UVR for efficient vitamin D synthesis, hence natural selection favored the evolution of light skin [8], [11]. This is indirectly supported by the observation that candidate pigmentation genes are collectively enriched by high-FST single-nucleotide polymorphisms [SNP] [12]–[14]. Furthermore, data mining of publicly available datasets, such as HapMap, Perlegen and Human Genome Diversity Project [HGDP], has provided evidence of selection signals in pigmentation-related genes in one or more populations [see [15] and references therein], [16] thus elucidating the history of human adaptation to local environments for this complex trait.
One of the key pigmentation genes in humans is SLC24A5 [OMIM 609802]. It is located on chromosome 15q21.1 and encodes a protein called NCKX5. The association of this gene with lighter pigmentation was initially discovered in zebrafish [4]. Using admixed populations, it was further demonstrated in this study [4] that a non-synonymous variant [ref SNP ID: rs1426654] in the third exon of this gene explains 25–38% of the skin color variation between Europeans and West Africans. The ancestral [G] allele of the SNP predominates in African and East Asian populations [93–100%], whereas the derived [A] allele is almost fixed in Europe [98.7–100%] [4]. Functional assays of this gene suggested its direct involvement in human melanogenesis through cation-exchange activity [17], [18]. However, the fact that the ancestral [G] allele is virtually fixed not only in Africans but also in East Asians suggests that light skin at high latitudes evolved independently in East and West Eurasia [19]. Genome-wide scans have also identified SLC24A5 as one of the most important “hot spots” for positive selection in Europeans, thereby supporting the role of natural selection acting on this gene [4], [20], [21].
Populations of South Asia live at lower latitudes than would be expected to require selection for lighter skin color on the basis of improved vitamin D synthesis [8]. Nevertheless, South Asians do exhibit a wide variation in skin color [22]. Two previous studies have assessed the genetics of skin pigmentation variation in expatriates from South Asia. The first of these [6] concluded that non-synonymous variants at three genes, SLC24A5, SLC45A2 [OMIM 606202], and TYR [OMIM 606933], collectively contribute to variation in skin pigmentation in South Asians, with SLC24A5 showing the largest effect. The second study on common disease variants suggested high prevalence of the light skin associated allele of SLC24A5 in Asian Indians [23]. Nevertheless, both the studies involved populations that were structured and represented only a small range of the vast ethnic and genetic landscape of South Asia. Hence, comprehensive assessment of this phenotypic trait in native populations of South Asia has been lacking so far.
Therefore, in the present study, we sought to address the following objectives. First, we aimed to quantify the amount of skin pigmentation variation that can be explained by the rs1426654 SNP of SLC24A5 in a homogeneous cohort of 1228 individuals from South Asia. Second, we studied the geospatial pattern of rs1426654-A allele in the Indian subcontinent using 1573 individuals from 54 populations and investigated how various factors influence its distribution. Third, we aimed to uncover the fine-scale genetic variation of SLC24A5 and determined the coalescence age of rs1426654 by resequencing 11.74 kb in a diverse set of 95 individuals. Lastly, we assessed whether SLC24A5 resequencing data and genome-wide genotype data were in concordance with the earlier reported evidence of positive selection in Europeans, and tested for any further evidence of selection among the studied populations. Our results confirm that rs1426654 plays a key role in pigmentation variation, while in-depth study of the light skin associated allele [rs1426654-A] among Indian populations reveals that the genetic architecture of skin pigmentation in South Asia is quite complex. The present study also provides important insights on evidence of positive selection and the evolutionary history of this light skin associated allele.
Results
Variation of melanin index in South Asia and its association with rs1426654 SNP
Phenotypic assessment of melanin index [MI] across 1674 individuals from two distinct cohorts, Cohort A and Cohort B [see Materials and Methods; Tables 1, S1 and S2] demonstrated a wide variation in skin color [MI 28–79] in South Asia. Comparison with published datasets for the regions of the world revealed that the observed range in South Asians was three times greater than that in East Asians and Europeans and comparable to that of Southeast Asians [Table 1]. Notably, Cohort A [n = 1228] which included individuals from three closely related agricultural castes of Andhra Pradesh in South India, shows remarkable variation in skin color [MI 30–64], similar to heterogeneous pool of samples in Cohort B [MI 28–79]. ______________
Although we observe a considerable local heterogeneity, there is a general trend of rs1426654-A allele frequency being higher in the Northern [0.70±0.18] and Northwestern regions [0.87±0.13], moderate in the Southern [0.55±0.22], and very low or virtually absent in Northeastern populations of the Indian subcontinent [Figure 2, Table S6]. Notably, the Onge and the Great Andamanese populations of Andaman Islands also showed absence of the derived-A allele. Given the fact that one can observe a pronounced latitudinal cline for skin pigmentation across world populations, we also sought to test the observed derived-A allele frequencies in terms of absolute latitude and longitude in South Asia. We found that the rs1426654-A allele frequency in South Asia does not significantly correlate with latitude [r = 0.23, p = 0.15]. However, a significant negative correlation with longitude [r = −0.49; p = 0.002] was observed.
We found that the Tibeto-Burman and the Austroasiatic language families have the lowest frequencies of the A allele [ and Table S6]. The rs1426654-A allele frequency was significantly higher in Indo-European speakers than in other language groups [Table S6]. In particular, there was a significant difference [p<0.001] between the A allele frequencies of the Indo-European and the Dravidian speaking groups. We found that both language and geography have a significant influence on rs1426654-A allele frequency, as revealed by Mantel tests [p<0.001].
We also studied the geospatial pattern of rs1426654-A allele frequencies at the global level using 2763 subjects from previously published data [Table S7] and 1446 individuals from the present study [Table S5]. The isofrequency map illustrates high frequencies of the rs1426654-A allele in Europe, Middle East, Pakistan, moderate to high frequencies in Northwest and Central Asia, while being almost absent in East Asians and Africans with notable exceptions in Bantu [Southwest], San, Mandeka, and Ethiopians [Table S7, Figure 2]. As rs1426654-A allele frequency was found to be higher in West Eurasian populations that are known to share one of the genome-wide ancestry components of South Asia [24], [25], we sought to test the correlation between the derived-A allele frequency and the proportion of the West Eurasian ancestry component [as depicted by the “light green component” in [24]] for the studied populations. For this, we used the genome-wide information available on Indian populations from literature [24]–[28] [Table S8] and relevant global reference populations to perform the ADMIXTURE run. Population structure as inferred by ADMIXTURE analysis at K = 7 is shown in Figure S2A. The proportions of k5 light green ancestry component obtained at K = 7 for the populations studied were plotted against the rs1426654-A allele frequency available for all populations and South Asia in particular [Figure S2B]. As shown in Figure S2B, we obtained a significant positive correlation for South Asian populations [r = 0.90, p<0.0001] but a weak, although significant correlation when all populations sharing the k5 component [r = 0.64, p = 0.04] were considered.
We estimated the coalescence time of the rs1426654 mutation at 28,100 years [95% CI - 4,900 to 58,400 years] using BEAST. Using the same mutation rate, the coalescent age estimated by rho statistics was 21,702 years ±10,282 years. Despite the different assumptions used in the two coalescent age estimation methods, both the age estimates show substantial overlap.
Discussion
Effect size of the rs1426654 SNP and its association with pigmentation variation in South Asia
A number of previous studies have focused on admixed populations in the search for genes that determine skin pigmentation variation in humans [4], [5], [33]–[35]. Our formal tests for association, using a large homogenous population from South India [Cohort A] as well as a heterogeneous pool of samples across India [Cohort B], demonstrated a highly significant effect of SLC24A5 on skin pigmentation. Further analysis of Cohort A revealed that this SNP determines most of the variation between the pigmentation extremes and contributes about 22–32% of the total skin color variation, thus suggesting that SLC24A5 plays a key role in the pigmentation diversity observed among South Asians.
Furthermore, confounding effect of population structure on the genetics of skin pigmentation, evident in Cohort B suggests that the marked population substructure of South Asians must be taken into account when genetic association studies are conducted in these populations.
The spread of rs1426654-A allele in South Asia
Our extensive survey of rs1426654-A allele frequency in the Indian subcontinent reveals an average frequency of 0.53 with a substantial variation among populations, ranging from 0.03 to 1 [Table S4]. This finding stands in contrast to the previous understanding of the spread of this allele, where a study [23] based on a cohort of 15 Indian ethnic groups sampled in the US [n = 576], estimated the average A allele frequency at 0.86, with a relatively low level of variation among populations [observed range 0.70 to 1]. The most plausible cause of this discordance might be that fewer populations were included in the former study and the groups were defined by their generic linguistic affiliation in major branches of the Dravidian and Indo-European languages, rather than by finer resolution of the endogamous units. Notably, in the subset of 8 populations that could be characterized on a similar basis in both studies, the estimates of A allele frequencies did not diverge significantly in their combined averages [Table S14]. Therefore, these comparisons suggest that sampling strategies are pivotal in determining the extent of genetic diversity observed in Indian populations and that sampling of expatriates may have a homogenizing effect. Moreover, the expatriates are known to represent mainly urban populations of India, which constitute only 30% [Census 2011; http://censusindia.gov.in/] of the total population of the subcontinent, and therefore are unlikely to be representative of the wealth of genetic variation harbored within the subcontinent.
Factors shaping the complex pattern of the rs1426654-A allele in South Asia
Our quest to determine whether and to what extent the distribution of the rs1426654 derived- A allele frequency in South Asian populations correlates with language and/or geography revealed that both of these variables have a significant predictive value on allele frequencies. In particular, we found that although frequencies among populations studied vary considerably, this polymorphism has an evident geographic structure with higher frequencies of the derived allele in North and Northwest regions and a declining pattern as one moves further South and East [Table S5, Figure 2]. However, when we plotted the rs1426654-A allele frequency against the geographical coordinates of our sampled populations, we found a significant correlation with longitude but not with latitude. The lack of a clear latitudinal [North-South] cline in the A allele frequency, which would have been expected under the model of natural selection, could be partly explained by the complexity of the South Asian genetic landscape, influenced by differences in population histories shaped by various micro-level migrations within the subcontinent, strict endogamy and social barriers. For example, Saurashtrians, who migrated from “Saurashtra” region of Gujarat to South India [Madurai] for work, have a relatively high rs1426654-A allele frequency of 0.70. It is believed that those Saurashtrians presently dwelling in Madurai were invited by Nayak kings for their expertise in silk-weaving [36]. Similarly, Toda have higher A allele frequency [0.86] compared to Kurumba [0.20], their geographical neighbors, most likely due to their higher proportion of West Eurasian ancestry which is supported by Y chromosome evidence [37]. Notably, Brahmins, irrespective of their geographic source [North, Central or South India] have higher A allele frequency [Table S5]. Conversely, the higher longitudinal correlation could be due to the fact that Tibeto-Burman and Austroasiatic speakers are characterized by very low A allele frequency [Table S6] because of their East Asian ancestry [26], [38]. Therefore, their inclusion in our sampling might have resulted in the inflation of the longitudinal correlation coefficient.
Coalescence age estimate of the rs1426654-A allele
Although the last decade has witnessed significant improvement in the understanding of the genetic basis of skin pigmentation, our knowledge about the exact mechanisms behind the evolution of light skin in humans is still incomplete. The genetic evidence that has accumulated till date suggests a complex evolutionary history for skin pigmentation. It has been argued that natural selection in response to UVR had a causative role in the evolution of light skin color at high latitudes [8], [39], [40]. Evidence of population-specific signatures of selection of pigmentation genes at different timescales suggests that the evolution of light skin was not a one-step process [41], [42] but a consequence of multiple events or episodes during human evolution. It appears that some of the mutations which have been associated with light skin started to accumulate relatively early in modern human history in the proto-Eurasian populations following the Out-of-Africa expansion, whereas other mutations arose after the divergence of East and West Eurasian populations [4], [19], [29], [41].
Hence, studies focusing on the time-scale of genetic changes in pigmentation genes are vital for understanding the complex evolutionary history of human skin pigmentation. Therefore, in this study, we focused on providing an age estimate of the rs1426654 mutation, which has a major effect on skin pigmentation in West Eurasian and South Asian populations. Notably, previous studies providing age estimates for this locus have been mostly confined to the estimation of onset of selective sweep rather than the coalescence time of the mutation. A study of extended haplotype homozygosity in HapMap populations estimated that the most intense signals of selection detected in European and East Asian populations are found in haplotypes which extend 0.52 cM on average in length [20]. Assuming a star-shaped genealogy and a generation time of 25 years, the authors dated the peak of these signals to ~6.6 KYA [20]. They also observed that the second-longest haplotype [1.15 cM] in Europe includes SLC24A5, where rs1426654-A was found to be fixed. Using the same formula used by Voight [20] to date the average peaks of selection signals in Europe and East Asia, the selective sweep specifically at SLC24A5 in the HapMap European sample can be dated to ~3 KYA. Besides this, a recent study by Beleza [42], focusing on analyses of diversity in microsatellite loci, estimated that the selective sweep at SLC24A5 occurred around 11.3 KYA [95% CI, 1–55.8 KYA] and 18.7 KYA [5.8–38.3 KYA] under additive and dominant models, respectively [42].
Our Bayesian coalescent age estimate of the rs1426654-A allele at ~28 KYA [95% HPD, 5–58 KYA], as well as the rho-based estimate at 21.7 [±10.3] KYA, are older in their point estimates than both of the above selective sweep date estimates, although these age estimates have broad and overlapping error margins. This finding is not surprising because sweeps can also operate on standing variation. Besides this, both our rho-based point estimate and Bayesian mean age estimate postdate the estimated time of the split between Europeans and Asians calculated by Scally [43] using a similar mutation rate. Although our confidence intervals cannot rule out entirely the possibility of older dates [>28 KYA], our findings are broadly consistent with the evolutionary model of skin pigmentation proposed in earlier studies [41], [42], [44]. It appears that the most plausible scenario is that light skin evolved as an adaptation to local environmental conditions as humans started moving to northerly latitudes, with the initial phase of skin lightening occurring in proto Eurasian populations, while genetic variation in SLC24A5 formed the later phase which led to lighter skin in Europeans and South Asians, but not East Asians. This was followed by a European-specific selective sweep, which favored the rapid spread of this mutation in these populations. Our coalescence age estimates of 28 KYA [95% HPD 5–58 KYA] show wide margins, also evident in the earlier sweep date estimates for the gene [42]. This can be due to the fact that the power of our analysis was limited by the need to reduce our sequence range to a subset of sites from a region with sufficiently high LD around the rs1426654-A allele and very low level of sequence variation. Therefore, we speculate that narrowing down the coalescence age estimates and specifying the geographic source of the rs1426654-A allele will depend rather on the success of ancient DNA studies than on more extensive sequencing.
Evidence for positive selection
Earlier studies have highlighted SLC24A5 as one of the top candidate genes demonstrating evidence for positive selection in Europeans [4], [13], [20], [21], [29], [30] and in Middle Eastern and Pakistani populations from South Asia [13], [29] on the basis of either FST or extended haplotype homozygosity from genotype data. Here, relying on our previous scans of extended haplotype homozygosity on Indian populations [24], we note that both XP-EHH and iHS suggest that positive selection has occurred in North Indian [within top 5% and top 1% respectively] but not in South Indian populations. One possible explanation for the regional differences in empirical ranks of the SLC24A5 in India could be the “melanin threshold” hypothesis [45]. According to this hypothesis, natural selection affects the variation in pigmentation phenotype only up to a certain adaptive optimum, beyond which individuals may show variation that is subject to other factors such as admixture, genetic drift etc. However, differently from the expectations of this hypothesis, we do observe high range of melanin indices both in North and South Indian populations of Cohort B [Table S2]. Furthermore, the high positive correlation of rs1426654-A allele with the light-green South Asian ancestry component [Figure S2A] advocates that the rs1422654-A allele frequency patterns in India could be also explained by demographic history of the populations in addition to selection. It is also possible that while XP-EHH and iHS tests have increased power to detect selection signatures associated with high allele frequencies, the low ranking position of SLC24A5 in selection scans of South Indians is due to the overall lower frequency of the rs1422654-A allele.
Therefore, the complex patterning of light skin allele in India and its correlation with geography, language, and ancestry component observed in the present study, portrays an interesting interplay between selection and demographic history of the populations. This stands in contrast to Europe where the frequency of the light skin associated allele of SLC24A5 has almost reached to fixation and seems to be attributable solely to natural selection. This aspect of skin pigmentation variation observed in South Asians is pivotal in understanding the different mechanisms that contribute to the global skin pigmentation variation and in further understanding of this complex phenotypic trait.
To summarize, we have provided evidence using a homogeneous cohort that the rs1426654 SNP plays a key role in skin pigmentation variation in South Asia. We have shown that the rs1426654-A allele is widespread in the Indian subcontinent and its complex pattern is a result of combination of processes involving selection and demographic history of populations, influenced by their linguistic and geographic affiliations. Phylogenetic analyses of resequencing data confirm that the rs1426654-A allele in West Eurasian and South Asian populations occurs on the same haplotype background. Both sequence and genome-wide genotype data confirm evidence of positive selection in Europeans, while the latter supports further evidence of selection in populations of Middle East, Pakistan, Central Asia and North India but not in South India. We date the coalescence of the light skin allele [rs1426654-A] to 22–28 KYA [95% CI, 5–58 KYA]. However, since this allele has become fixed in many populations across its current distribution, we propose that ancient DNA research might have greater potential to improve our understanding of when and where it first appeared
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Interesting paper, but of course this was already known.
quote: The L374F polymorphism of the SLC45A2 gene, encoding the membrane-associated transporter protein that plays an important role in melanin synthesis, has been suggested to be associated with skin color in human populations. In this study, the detailed distribution of the 374f and 374l alleles has been investigated in 2,581 unrelated subjects from 36 North, East, West, and Central African populations. We found once more the highly significant (p 0.001) correlation coefficient (r = 0.957) cline of 374f frequencies with degrees of latitude in European and North African populations. Almost all the African populations located below 16° of latitude are fixed for the 374l allele. Peul, Toucouleur, and Soninké populations have 374l allele frequencies of 0.06, 0.03, and 0.03, respectively.
Near Fixation of 374l Allele Frequencies of the Skin Pigmentation Gene SLC45A2 in Africa
quote:The two genes SLC24A5 and SLC45A2 were recently identified as major determinants of pigmentation in humans and in other vertebrates. The allele p.A111T in the former gene and the allele p.L374F in the latter gene are both nearly fixed in light-skinned Europeans, and can therefore be considered ancestry informative marker (AIMs). AIMs are becoming useful for forensic identification of the phenotype from a DNA profile sampled, for example, from a crime scene. Here, we generate new allelic data for these two genes from samples of Chinese, Uygurs, Ghanaians, South African Xhosa, South African Europeans, and Sri Lankans (Tamils and Sinhalese). Our data confirm the earlier results and furthermore demonstrate that the SLC45A2 allele is a more specific AIM than the SLC24A5 allele because the former clearly distinguishes the Sri Lankans from the Europeans. Authors
--Soejima M, Koda Y, Population differences of two coding SNPs in pigmentation-related genes SLC24A5 and SLC45A2.
Molecular genetics of human pigmentation diversity
Next Section Abstract
quote: Next Section Abstract
The genetic basis underlying normal variation in the pigmentary traits of skin, hair and eye colour has been the subject of intense research directed at understanding the diversity seen both between and within human populations. A combination of approaches have been used including comparative genomics of candidate genes and the identification of regions of the human genome under positive selection, together with genome-wide and specific allele association studies. Independent selection for different pigmentation gene sets has been found between Asian, European and African populations. Several genome-wide association studies for pigmentation have now been conducted and identified single nucleotide polymorphism (SNP) markers in known, TYR, TYRP1, OCA2, SLC45A2, SLC24A5, MC1R, ASIP, KITLG and previously unknown SLC24A4, IRF4, TPCN2, candidate genes. The contribution of SNP polymorphisms present in populations from South Asia have been tested and alleles found at TYR, SLC45A2 and SLC24A5 can largely account for differences between those of darkest and lightest skin reflectance using a simple additive model. Skin and hair colour associations in Europeans are found within a range of pigmentation gene alleles, whereas blue-brown eye colour can be explained by a single SNP proposed to regulate OCA2 expression. Functional testing of variant alleles has begun to connect phenotype correlations with biological differences. Variant MC1R alleles show direct correlations between the biochemical signalling properties of the encoded receptor and the red-hair fair skin pigmentation phenotype. Direct testing of a range of clonal melanocyte cultures derived from donor skin tissue characterized for three causal SNPs within SLC45A2, SLC24A5 and OCA2 has assessed their impact on melanin content and tyrosinase enzyme activity. From a culmination of genetic and functional studies, it is apparent that a number of genes impacting melanosome biogenesis or the melanin biosynthetic pathway are candidates to explain the diversity seen in human pigmentation.
Previous Section Next Section INTRODUCTION
It is astonishing that in a few short years, our understanding of the molecular genetics of human pigmentation has progressed from asking simple questions about what type and how many genes underlie the diversity of skin, hair and eye colour (1) to the identification of several of the major loci and polymorphisms responsible. There is a high degree of variation in colour (amount and type of melanin pigment) and skin type (responsiveness to UV exposure) apparent between and within human populations (Fig. 1), though only those with European ancestry show a large range of hair (2) and eye colours (3). This recent exponential rate of discovery of important pigmentation determining genes has been made through a combination of genetic, biochemical and cellular approaches, but undoubtedly it has been the ready access to the complete human genome sequence and documentation of a vast number of single nucleotide polymorphisms (SNPs: www.hapmap.org; genome.perlegen.com) in several populations (4,5) that is responsible for this expanding knowledge. The methods include comparative genomics of candidate genes such as those identified through studies of mouse coat colours (6) or fish pigmentation patterns (7,8), looking for regions under positive selection between human populations (9–12) that a priori include loci for pigmentation traits, together with genome-wide (13) and specific allele association studies (14) in individuals of defined phenotype. These genetic approaches and the insight they have provided into the pigmentary process will be the focus of this review; however, determination of the molecular mechanism of action, gene interaction and functional protein assays need to be considered to understand how allelic variation in pigmentation genes results in such a diversity of phenotypes in human populations.
quote:Originally posted by IronLion: Can you summarize what you just posted and then clarify your stance? Thank you...
In summery and my stance, it's that these depigmentation alleles as fixed and / or unfixed are found in Asian and African populations, before in Europeans. As I have always stated.
This is for obvious reasons,
quote: ".. it appears that Europeans are about two-thirds Asians and one-third African."
--Luigi Luca Cavalli-Sforza (2001). Genes, peoples and languages. FARRAR STRAUS AND GIROUX Publishers
quote:Originally posted by the lioness,: A significant correlation between skin color and ultraviolet radiation [UVR] levels observed at the global scale suggests that natural selection plays an important role in determining the distribution of this phenotypic trait [8]. The evolution of dark skin at low latitudes has been mainly accredited to the requirement of photo-protection against UVR which causes sunburn and skin cancer, whereas the evolution of light skin has been most commonly associated with vitamin D deficiency [9], [10]. It has been proposed that as humans started to colonize higher latitudes, where UVR levels were lower, dark skin could not absorb sufficient UVR for efficient vitamin D synthesis, hence natural selection favored the evolution of light skin [8], [11]. This is indirectly supported by the observation that candidate pigmentation genes are collectively enriched by high-FST single-nucleotide polymorphisms [SNP] [12]–[14]. Furthermore, data mining of publicly available datasets, such as HapMap, Perlegen and Human Genome Diversity Project [HGDP], has provided evidence of selection signals in pigmentation-related genes in one or more populations [see [15] and references therein], [16] thus elucidating the history of human adaptation to local environments for this complex trait.
Ha,ha,ha,ha:
These lies and Bullsh1t has been debunked a zillion times, yet Albinos keep introducing it. That's the height of delusion and stupidity: you keep doing the same thing while waiting for a different outcome.
CENTRAL ASIAN PEOPLE:
IRISH REDHEADS
Could Ireland’s cloudy weather be the reason for the stereotypical red hair?
Our fair skin and red hair could be “deliberate genetic adaptation” so we absorb more vitamin D when it’s sunny By CATHY HAYES, IrishCentral Staff Writer
posted
Which likely explains the oldest Northern Europeans. The Saami people,
Ancient DNA Reveals Prehistoric Gene-Flow from Siberia in the Complex Human Population History of North East Europe
quote: Abstract
North East Europe harbors a high diversity of cultures and languages, suggesting a complex genetic history. Archaeological, anthropological, and genetic research has revealed a series of influences from Western and Eastern Eurasia in the past. While genetic data from modern-day populations is commonly used to make inferences about their origins and past migrations, ancient DNA provides a powerful test of such hypotheses by giving a snapshot of the past genetic diversity. In order to better understand the dynamics that have shaped the gene pool of North East Europeans, we generated and analyzed 34 mitochondrial genotypes from the skeletal remains of three archaeological sites in northwest Russia. These sites were dated to the Mesolithic and the Early Metal Age (7,500 and 3,500 uncalibrated years Before Present). We applied a suite of population genetic analyses (principal component analysis, genetic distance mapping, haplotype sharing analyses) and compared past demographic models through coalescent simulations using Bayesian Serial SimCoal and Approximate Bayesian Computation. Comparisons of genetic data from ancient and modern-day populations revealed significant changes in the mitochondrial makeup of North East Europeans through time. Mesolithic foragers showed high frequencies and diversity of haplogroups U (U2e, U4, U5a), a pattern observed previously in European hunter-gatherers from Iberia to Scandinavia. In contrast, the presence of mitochondrial DNA haplogroups C, D, and Z in Early Metal Age individuals suggested discontinuity with Mesolithic hunter-gatherers and genetic influx from central/eastern Siberia. We identified remarkable genetic dissimilarities between prehistoric and modern-day North East Europeans/Saami, which suggests an important role of post-Mesolithic migrations from Western Europe and subsequent population replacement/extinctions. This work demonstrates how ancient DNA can improve our understanding of human population movements across Eurasia. It contributes to the description of the spatio-temporal distribution of mitochondrial diversity and will be of significance for future reconstructions of the history of Europeans.
Author Summary
The history of human populations can be retraced by studying the archaeological and anthropological record, but also by examining the current distribution of genetic markers, such as the maternally inherited mitochondrial DNA. Ancient DNA research allows the retrieval of DNA from ancient skeletal remains and contributes to the reconstruction of the human population history through the comparison of ancient and present-day genetic data. Here, we analysed the mitochondrial DNA of prehistoric remains from archaeological sites dated to 7,500 and 3,500 years Before Present. These sites are located in North East Europe, a region that displays a significant cultural and linguistic diversity today but for which no ancient human DNA was available before. We show that prehistoric hunter-gatherers of North East Europe were genetically similar to other European foragers. We also detected a prehistoric genetic input from Siberia, followed by migrations from Western Europe into North East Europe. Our research contributes to the understanding of the origins and past dynamics of human population in Europe.
[...]
Coalescent simulations
In coalescent simulation analyses we considered the ancient populations of aUzPo, aBOO, Central/East/Scandinavian European hunter-gatherers (aHG [12], [14], aPWC [13]), and the modern populations of NEE, CE, and Saami (saa). Population statistics (haplotype diversity and fixation indexes, FST) for the ancient and extant populations were calculated in Arlequin version 3.11 (Table 2, [91]).
posted
Please Albinos, no more threads like this. I get tired of repeating myself. No matter how many times you try it, simply looking at people who actually live in low Sunlight environments will always expose your lie.
THIS IS ALBINISM, IT HAS NOTHING TO DO WITH LATITUDE.
posted
Thing is Mike as I have said time & time again THOSE PEOPLE ARE NOT WHITE, they are NOT of my people & will NEVER be.
Posts: 3257 | From: Madisonville, KY USA | Registered: Nov 2011
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quote:Originally posted by DHDoxies: Thing is Mike as I have said time & time again THOSE PEOPLE ARE NOT WHITE, they are NOT of my people & will NEVER be.
You keep ranting/ iterating the same. Like some delusional dumbass.
Why don't you give explanation too your claims, for a change. Because all you do is trying to distract and divert the subject. Due to lack of the subject.
Posts: 22234 | From: האם אינכם כילדי הכרית אלי בני ישראל | Registered: Nov 2010
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posted
Troll Patrol I have already explained why Albinos of other races are not White people.
Albino Negro = Still a Negro
Albino Mongol = Still a Mongol (Asian)
Albino Amerindian = Still an Amerindian
Albino White = Still a White person (European)
Anyhow feel free to explain in layman's terms what you meant with your other post. I'm NOT a geneticist after all. BTW, why is it you Black supremacists call everyone who doesn't agree with you delusional, schizophrenic, etc???
Posts: 3257 | From: Madisonville, KY USA | Registered: Nov 2011
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quote:Originally posted by Troll Patrol aka Ish Gebor: In summery and my stance, it's that these depigmentation alleles as fixed and / or unfixed are found in Asian and African populations, before in Europeans. As I have always stated.
quote:Originally posted by DHDoxies: Troll Patrol I have already explained why Albinos of other races are not White people.
Albino Negro = Still a Negro
Albino Mongol = Still a Mongol (Asian)
Albino Amerindian = Still an Amerindian
Albino White = Still a White person (European)
Anyhow feel free to explain in layman's terms what you meant with your other post. I'm NOT a geneticist after all. BTW, why is it you Black supremacists call everyone who doesn't agree with you delusional, schizophrenic, etc???
Is that your "scientific" evaluation?
Read my post here prior to this one. And try to comprehend.
By the way, you out of all people should not fetch on calling people "supremacist" when you are a supremacist brain wrecked Appalachian.
THANKS FOR YOUR TIME....
quote:"Cracker," the old standby of Anglo insults was first noted in the mid 18th century, making it older than the United States itself. It was used to refer to poor whites, particularly those inhabiting the frontier regions of Maryland, Virginia and Georgia. It is suspected that it was a shortened version of "whip-cracker," since the manual labor they did involved driving livestock with a whip (not to mention the other brutal arenas where those skills were employed.) Over the course of time it came to represent a person of lower caste or criminal disposition, (in some instances, was used in reference to bandits and other lawless folk.)
-Southern U.S. derogatory term for "poor, white trash" (1766), probably from mid-15c. crack "to boast" (e.g. not what it's cracked up to be), originally a Scottish word. Cf. Latin crepare "to rattle, crack, creak," with a secondary figurative sense of "boast of, prattle, make ado about.
Not so glorious after all, isn't it? Posts: 22234 | From: האם אינכם כילדי הכרית אלי בני ישראל | Registered: Nov 2010
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Science 20 April 2007: Vol. 316 no. 5823 p. 364 DOI: 10.1126/science.316.5823.364a
NEWS FOCUS
AMERICAN ASSOCIATION OF PHYSICAL ANTHROPOLOGISTS MEETING European Skin Turned Pale Only Recently, Gene Suggests Ann Gibbons
PHILADELPHIA, PENNSYLVANIA-- At the American Association of Physical Anthropologists meeting, held here from 28 to 31 March, a new report on the evolution of a gene for skin color suggested that Europeans acquired pale skin quite recently, perhaps only 6000 to 12,000 years ago. (Read more.)
posted
Troll Patrol, I will state once again and do try to get it through your head. A White person defending/claiming their history, heritage, identity, etc is NOT being a White supremacist. A White person telling a Non White Albino that they can not be part of our people is NOT being racist or White supremacist. BTW, I have NEVER in my time here claimed that Blacks or any other Non-White was inferior. YOU are the one who claims that Whites are inferior & Blacks are superior so exactly who is the supremacist LOL.
Posts: 3257 | From: Madisonville, KY USA | Registered: Nov 2011
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quote:Originally posted by Troll Patrol aka Ish Gebor: You must have confused yourself with Mike then? Always trying to hide like a coward behind other people. When you are run out of arguments "again".
you didn't post anything contradictory to what I posted in fcat supporting it therefore if there was a debate on some issue going on it must have been in your mind.
see if you can lower a rope so Mike might be saved
Posts: 42918 | From: , | Registered: Jan 2010
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posted
I wish some you brothas would slow down on the picture spamming and knee jerk reaction. PLEASE!!!! First read the paper, 2nd understand it. I guess some of us have our strengths.
This paper is as ground breaking as the recent Shriver et al paper on the Cape Verde. Maybe the black greek (herodotus) over at ESR will read it and would stop citing 15 year old outdated studies. HGDP and HAPMAP, GENOGRAPHIC Project as I said before is go to change the landscape and age old racialist beliefs. I will post on it on ESR. As I said – there are no European genes. This paper is in agreement with that Shriver 2013 paper. Infact it cites the Norton/Kittles paper which some of you may know the connection. Shriver was also the co-author on that one. He was Norton’s boss. Kivislid and Villems are the big dog on this one. I respect Kivislid work. See Dhoxie…I like some white people. Some researchesr try to remain honorable/honest with data they disclosed. They try not to falisfy data. Instead they may keep it hidden in Supplementals or spin BS with the data. READ THE STUDY!!!!!!!
Posts: 12143 | From: When you have eliminated the impossible, whatever remains, however improbable | Registered: Jun 2007
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posted
This is a keeper.....proving yet again all genes are African. Damn!!!!
-------------------- Without data you are just another person with an opinion - Deming Posts: 12143 | From: When you have eliminated the impossible, whatever remains, however improbable | Registered: Jun 2007
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quote:Originally posted by Troll Patrol aka Ish Gebor: You must have confused yourself with Mike then? Always trying to hide like a coward behind other people. When you are run out of arguments "again".
you didn't post anything contradictory to what I posted in fcat supporting it therefore if there was a debate on some issue going on it must have been in your mind.
see if you can lower a rope so Mike might be saved
Yep, and it disputes what you've been fighting for a very long time.
Now you have to kneel to Mike's hypothesis.
You are the weakest link... Posts: 22234 | From: האם אינכם כילדי הכרית אלי בני ישראל | Registered: Nov 2010
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quote:Originally posted by DHDoxies: Troll Patrol, I will state once again and do try to get it through your head. A White person defending/claiming their history, heritage, identity, etc is NOT being a White supremacist. A White person telling a Non White Albino that they can not be part of our people is NOT being racist or White supremacist. BTW, I have NEVER in my time here claimed that Blacks or any other Non-White was inferior. YOU are the one who claims that Whites are inferior & Blacks are superior so exactly who is the supremacist LOL.
Now that you have been able, with my help, to sort out the real meaning of the word cracker. And not the story that was roaming in "Appalachian land". To give yourself a boost.
Cracker, I have posted peer reviewed sources.
So your feeble minded Appalachian opinion is irrelevant.
What science tells is that the genetic markers exist out of the same alleles fixed and unfixed. And these alleles likely slowly became stable due to the melting of the ice and cold reduction, fluctuating Holocene period. These alleles are found in Africans as unfixed and fixed in Europeans. You dumbass.
The same goes for blonde hair and blue eyes btw.
Therefore, Europeans are 1/3 African, 2/3 Asian, as I have posted before, you dumb cracker.
Blue-Eyed Humans Have A Single, Common Ancestor
What is the genetic mutation
“Originally, we all had brown eyes”, said Professor Eiberg from the Department of Cellular and Molecular Medicine. “But a genetic mutation affecting the OCA2 gene in our chromosomes resulted in the creation of a “switch”, which literally “turned off” the ability to produce brown eyes”. The OCA2 gene codes for the so-called P protein, which is involved in the production of melanin, the pigment that gives colour to our hair, eyes and skin. The “switch”, which is located in the gene adjacent to OCA2 does not, however, turn off the gene entirely, but rather limits its action to reducing the production of melanin in the iris – effectively “diluting” brown eyes to blue. The switch’s effect on OCA2 is very specific therefore. If the OCA2 gene had been completely destroyed or turned off, human beings would be without melanin in their hair, eyes or skin colour – a condition known as albinism.
Limited genetic variation
Variation in the colour of the eyes from brown to green can all be explained by the amount of melanin in the iris, but blue-eyed individuals only have a small degree of variation in the amount of melanin in their eyes. “From this we can conclude that all blue-eyed individuals are linked to the same ancestor,” says Professor Eiberg. “They have all inherited the same switch at exactly the same spot in their DNA.” Brown-eyed individuals, by contrast, have considerable individual variation in the area of their DNA that controls melanin production.
Professor Eiberg and his team examined mitochondrial DNA and compared the eye colour of blue-eyed individuals in countries as diverse as Jordan, Denmark and Turkey. His findings are the latest in a decade of genetic research, which began in 1996, when Professor Eiberg first implicated the OCA2 gene as being responsible for eye colour.
Nature shuffles our genes
The mutation of brown eyes to blue represents neither a positive nor a negative mutation. It is one of several mutations such as hair colour, baldness, freckles and beauty spots, which neither increases nor reduces a human’s chance of survival. As Professor Eiberg says, “it simply shows that nature is constantly shuffling the human genome, creating a genetic cocktail of human chromosomes and trying out different changes as it does so.”
quote:Originally posted by Troll Patrol aka Ish Gebor:
quote:Originally posted by the lioness,:
quote:Originally posted by Troll Patrol aka Ish Gebor: You must have confused yourself with Mike then? Always trying to hide like a coward behind other people. When you are run out of arguments "again".
you didn't post anything contradictory to what I posted in fcat supporting it therefore if there was a debate on some issue going on it must have been in your mind.
see if you can lower a rope so Mike might be saved
Yep, and it disputes what you've been fighting for a very long time.
Now you have to kneel to Mike's hypothesis.
You are the weakest link...
Explain what disputes what I've been saying and how it supports Mikes hypothesis.
I dont think you will be able to because it is obvious you are very confused and dont undersand the articles you post
Posts: 42918 | From: , | Registered: Jan 2010
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quote:Originally posted by Troll Patrol aka Ish Gebor:
quote:Originally posted by the lioness,:
quote:Originally posted by Troll Patrol aka Ish Gebor: You must have confused yourself with Mike then? Always trying to hide like a coward behind other people. When you are run out of arguments "again".
you didn't post anything contradictory to what I posted in fcat supporting it therefore if there was a debate on some issue going on it must have been in your mind.
see if you can lower a rope so Mike might be saved
Yep, and it disputes what you've been fighting for a very long time.
Now you have to kneel to Mike's hypothesis.
You are the weakest link...
Explain what disputes what I've been saying and how it supports Mikes hypothesis.
I dont think you will be able to because it is obvious you are very confused and dont undersand the articles you post
Look at the pictures Mike posted, look at the pictures I've posted along with the study I have posted. Especially the place of origin and migrational route.
What does this tell you? Hmmm dumbo.
If there is someone here who doesn't understand it, it's you. As has been proving countless of times.
Therefore your only choice becomes trolling the forum with irrelevant pictures, multiple trollcounts, hiding like a cowered behind people's name, twisting people's post and lie about what they've posted originally etc...
Posts: 22234 | From: האם אינכם כילדי הכרית אלי בני ישראל | Registered: Nov 2010
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quote:Originally posted by xyyman: I wish some you brothas would slow down on the picture spamming and knee jerk reaction. PLEASE!!!! First read the paper, 2nd understand it. I guess some of us have our strengths.
This paper is as ground breaking as the recent Shriver et al paper on the Cape Verde. Maybe the black greek (herodotus) over at ESR will read it and would stop citing 15 year old outdated studies. HGDP and HAPMAP, GENOGRAPHIC Project as I said before is go to change the landscape and age old racialist beliefs. I will post on it on ESR. As I said – there are no European genes. This paper is in agreement with that Shriver 2013 paper. Infact it cites the Norton/Kittles paper which some of you may know the connection. Shriver was also the co-author on that one. He was Norton’s boss. Kivislid and Villems are the big dog on this one. I respect Kivislid work. See Dhoxie…I like some white people. Some researchesr try to remain honorable/honest with data they disclosed. They try not to falisfy data. Instead they may keep it hidden in Supplementals or spin BS with the data. READ THE STUDY!!!!!!!
In the case the pictures were especially important as these motivated the studies being propelled.
You aren't the only reader, here. Some readers need more explanation to the story.
Posts: 22234 | From: האם אינכם כילדי הכרית אלי בני ישראל | Registered: Nov 2010
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quote:Originally posted by Troll Patrol aka Ish Gebor:
quote:Originally posted by xyyman: I wish some you brothas would slow down on the picture spamming and knee jerk reaction. PLEASE!!!! First read the paper, 2nd understand it. I guess some of us have our strengths.
This paper is as ground breaking as the recent Shriver et al paper on the Cape Verde. Maybe the black greek (herodotus) over at ESR will read it and would stop citing 15 year old outdated studies. HGDP and HAPMAP, GENOGRAPHIC Project as I said before is go to change the landscape and age old racialist beliefs. I will post on it on ESR. As I said – there are no European genes. This paper is in agreement with that Shriver 2013 paper. Infact it cites the Norton/Kittles paper which some of you may know the connection. Shriver was also the co-author on that one. He was Norton’s boss. Kivislid and Villems are the big dog on this one. I respect Kivislid work. See Dhoxie…I like some white people. Some researchesr try to remain honorable/honest with data they disclosed. They try not to falisfy data. Instead they may keep it hidden in Supplementals or spin BS with the data. READ THE STUDY!!!!!!!
In the case the pictures were especially important as these motivated the studies being propelled.
You aren't the only reader, here. Some readers need more explanation to the story.
translation:
Troll can't explain how he and Mike's knee jerk picture spams relate to the article
doesn't even relaize Mike said the article was quote " lies and Bullsh1t"
go ahead try to save your pride now, call me some names
Posts: 42918 | From: , | Registered: Jan 2010
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quote:Originally posted by Troll Patrol aka Ish Gebor:
quote:Originally posted by xyyman: I wish some you brothas would slow down on the picture spamming and knee jerk reaction. PLEASE!!!! First read the paper, 2nd understand it. I guess some of us have our strengths.
This paper is as ground breaking as the recent Shriver et al paper on the Cape Verde. Maybe the black greek (herodotus) over at ESR will read it and would stop citing 15 year old outdated studies. HGDP and HAPMAP, GENOGRAPHIC Project as I said before is go to change the landscape and age old racialist beliefs. I will post on it on ESR. As I said – there are no European genes. This paper is in agreement with that Shriver 2013 paper. Infact it cites the Norton/Kittles paper which some of you may know the connection. Shriver was also the co-author on that one. He was Norton’s boss. Kivislid and Villems are the big dog on this one. I respect Kivislid work. See Dhoxie…I like some white people. Some researchesr try to remain honorable/honest with data they disclosed. They try not to falisfy data. Instead they may keep it hidden in Supplementals or spin BS with the data. READ THE STUDY!!!!!!!
In the case the pictures were especially important as these motivated the studies being propelled.
You aren't the only reader, here. Some readers need more explanation to the story.
translation:
Troll can't explain how he and Mike's knee jerk picture spams relate to the article
doesn't even relaize Mike said the article was quote " lies and Bullsh1t"
go ahead try to save your pride now, call me some names
The pictures posted along explain what the first modern European people looked like. You weirdo. The pictures and the studies I've posted along the study you've posted show who these people were and why modern Europeans carry those specific fixed alleles. While African and Asia populations carry these as unfixed or sometimes as fixed.
Translation:
trolling lioness doesn't have any valid arguments.
So the main troll does what it does best, hide like a coward behind others. In this case it's Mike.
However, Mike stated the origin of modern Europeans a long time ago.
And in recent days I have posted a recent paper confirming what Mike stated all along.
So now the troll and and black woman impostor known as the lioness iterates nonsense. So the lioness doesn't have to admit another lose.
What Mike stated was that during the Paleolithic Europe was inhabited by African like people/ Homo Sapiens Sapiens. Which is correct. However, the particular study I've posted is about the Holocene.
quote: "...the Cro-Magnons, the presumed ancestors of modern Europeans....were more like present-day Australians or Africans..."
--Chris Stringer, African Exodus ((Michael Witzel, The Origins of the World's Mythologies) 2013)
quote:"The so-called Old Man [Cro-Magnon 1] became the original model for what was once termed the Cro-Magnon or Upper Paleolithic "race" of Europe.. there's no such valid biological category, and Cro-Magnon 1 is not typical of Upper Paleolithic western Europeans- and not even all that similar to the other two make skulls found at the site. Most of the genetic evidence, as well as the newest fossil evidence from Africa argue against continuous local evolution producing modern groups directly from any Eurasian pre-modern population.. there's no longer much debate that a large genetic contribution from migrating early modern Africans infuenced other groups throughout the Old World.“
--B. Lewis et al. 2008. Understanding Humans: Introduction to Physical
quote: If this analysis shows nothing else, it demonstrates that the oft-repeated European feeling that the Cro-Magnons are “us” (47) is more a product of anthropological folklore than the result of the metric data available from the skeletal remains.
--C. Loring Brace(2006) The questionable contribution of the Neolithic and the Bronze Age to European craniofacial form
quote: It has been proposed that heat adapted, relatively long-legged Homo sapiens from Africa replaced the cold adapted, relatively short-legged Homo neandertalensis of the Levant and Europe
--J Hum Evol 32 (1997a) 423], Bogin B, Rios L. et al.
quote: The subsequent post-28,000-B.P. Gravettian human sample of Europe includes numerous associated skeletons (Table 2) (Zilhão & Trinkaus 2002). Most of these specimens are fully modern in their morphology, and there is a persistence in them of both linear (equatorial) limb proportions and more "African" nasal morphology (Trinkaus 1981, Holliday 1997, Franciscus 2003). However, one Iberian specimen (Lagar Velho 1) exhibits Neandertal limb segment proportions and a series of relatively archaic cranial and postcranial features (Trinkaus & Zilhão 2002). In addition, central incisor shoveling, ubiquitous among the Neandertals, absent in the Qafzeh-Skhul sample, and variably present in the earlier European sample, persists at modest frequencies. And scapular axillary border dorsal sulci, an apparently Neandertal feature also absent in the Qafzeh-Skhul sample, is present
--Trinkaus 2005
quote: "Nor does the picture get any clearer when we move on to the Cro-Magnons, the presumed ancestors of modern Europeans. Some looked more like present-day Australians or Africans, judged by OBJECTIVE anatomical categorizations, as is the case with some early modern skulls from the Upper Cave at Zhoukoudian in China."
-- Am J Phys Anthropol. 1975 May;42(3):351-69,
quote:In modern humans, this elongation is a pattern characteristic of warm-adapted populations, and this physique may be an early Cro-Magnon retention from African ancestors. Similar retentions may be observed in certain indices of facial shape [ ...]
--Encyclopedia of Human Evolution and Prehistory: Second Edition by Eric Delson
quote:"others like Predomost and to a lesser degree Grimaldi and Teviec, are more prognathic like Skhul 5."
--Marta Mirazón Lahr. 2005. The Evolution of Modern Human Diversity:
quote: Archaeologist Ofer Bar-Yosef is an interpreter of ancient human history as told by barn owls, a sleuth in search of mankind's past, reading the ashes of campfires extinguished millennia ago and examining stone flakes for evidence of a human hand in their creation.
For much of his academic career, Bar-Yosef's focus has been the Stone Age - known as the Paleolithic - when early Homo sapiens went by the name Cro-Magnon and lived side by side with a human cousin, the Neanderthal.
His work, conducted with colleagues from the United States, France, and Israel, has focused on three Israeli caves that paint a picture of early habitation by modern humans migrating north out of Africa and a later migration by Neanderthals south out of southeast Europe or Turkey. It is this mix of human species and the later departure of Cro-Magnon man out of the Middle East to colonize Neanderthal-dominated Europe that fascinates Bar-Yosef.
Bar-Yosef, Harvard's MacCurdy Professor of Prehistoric Archaeology and head of the Peabody Museum's Stone Age Laboratory, is now shifting his attention to a later period, the New Stone Age, known as the Neolithic, when Homo sapiens first domesticated plants. He's particularly interested in the rise of agriculture, dubbed the Neolithic Revolution, a transforming event in human history that set the stage for early villages and the larger civilizations to come.
It's his interest in an earlier prehistoric revolution that spurs Bar-Yosef's investigation of the Neolithic. Bar-Yosef believes it was some type of technological revolution that gave Cro-Magnon humans the upper hand over Neanderthals some 35,000 years ago. It was at that time, after thousands of years of coexistence, that Cro-Magnon began to multiply rapidly, expanding into a Neanderthal-dominated Europe and into Asia. It is also at that time that Neanderthals began to decline, eventually disappearing entirely.
Some believe there was a change in the brain that explains Cro-Magnon success, though no evidence of it has been found from remains of the time. Perhaps it was a change in the brain or elsewhere that, though undetectable in remains that have survived, meant the difference for Cro-Magnons between merely surviving and thriving.
Bar-Yosef looks to more recent history for a different explanation. The Industrial Revolution also transformed human society, he points out, yet was clearly a product of human innovation, not human biological evolution. A future archaeologist looking back at that period of time might conclude that it was a neurological change that gave humans the sudden capacity for industrial innovation.
They'd be wrong. The Industrial Revolution was an accident of timing, the sudden flowering of centuries of slowly accumulating knowledge that triggered a cascading avalanche of industrial development.
Bar-Yosef asks why a similar revolution couldn't have happened 35,000 to 40,000 years ago, during the Upper Paleolithic. New technology, he said, could have made a huge difference in the success of early human communities.
"It was a new, improved hunting technique, probably coupled with a means for long-range communication, say drums, that enabled early groups of Cro-Magnon to become better hunters and better monitors of the environment, and to communicate that to others," Bar-Yosef surmises. "That would have led to better survival of babies, to population increase - more rapidly among Cro-Magnons than among Neanderthals.
Rice grain in a haystack?
Bar-Yosef's work on the agricultural revolution will take him to Turkey and China. Like the much later Industrial Revolution, experts agree that the Neolithic's agricultural revolution occurred as a result of a new technology - in this case the domestication of crop plants - and not some physiological change that suddenly made the time's human hunters better suited for farming.
The rise of agriculture had far-reaching effects. With the ability to plant crops, people were assured a more steady food supply. Agriculture led to more permanent settlements and, ultimately, to the rise of civilization.
While much is known about the rise of agriculture in the Near East, less is known of its progress in China. Looking for the location where rice was originally cultivated may seem like searching for a needle in a haystack, but Bar-Yosef said he and fellow scientists will use what they know about the climate of the period to determine likely environments where the progenitor wild rice plants might have grown. It is in these places, he said, that they will focus their search for early agricultural communities.
"Historians look at the Industrial Revolution, and most agree when and where it took place, but have different opinions on why," Bar-Yosef said. "The same thing with the Neolithic Revolution, people agree with when and where but not on why. In China, even where and when hasn't been found yet."
The micro-mammal trail
Bar-Yosef's scientific journey started in Kebara Cave in Israel in 1982. While excavating the cave, he and several collaborators found Neanderthal remains dating back to 60,000 years ago, fairly late in the Neanderthal timeline, which began some 300,000 years ago in Europe. The Neanderthals, it appeared, had been fairly late arrivals to the Mediterranean's eastern coastal region known as the Levant.
The group working at Kebara was using relatively new thermoluminescence and electron spin resonance dating techniques, an improvement over radiocarbon dating, which cannot date fossils earlier than 40,000 years ago. In addition to using the new techniques at Kebara, they applied them to the fossil-bearing layers at a nearby cave, Qafzeh.
Qafzeh, about 25 miles away, was a cave with an archaeological past. It was first excavated in the 1930s. It was excavated again in the 1960s by Bernard Vandermeerasch from the University of Bordeaux. Bar-Yosef did additional work there in the late 1970s with Vandermeerasch. Human fossils, mostly in well-organized burials, had been found in Qafzeh. The fossils resembled modern humans. Under the prevailing thought of the time - that Neanderthals were the ancestors of modern humans - the Qafzeh remains should be more recent than the Neanderthal remains at Kebara.
But Bar-Yosef had a feeling that wasn't the case.
His feeling stemmed from a combination of evidence, including climatic clues from sediment layers in the cave and studies of the remains of micro-mammals such as rats, mice, squirrels, and other small animals at Qafzeh conducted by the late Eitan Tchernov of Hebrew University.
Micro-mammals are an important indicator in figuring out who was living in a cave when. That's because the animals are the prey of barn owls - and barn owls only like caves without human lodgers. Barn owls also have a very archaeologist-friendly way of dining - they eat their small mammal meal and then regurgitate the bones, creating a litter of bones on the cave floor.
By classifying these bones and comparing them to a sequence of known layers, zooarchaeologists can tell not only what kind of mammals the owls were eating but also when. Mice, for example, are generally found in warmer and drier climates. By comparing layers with many mice bones with those dominated by other rodents, archaeologists can track the region's climate as it became wetter and drier over time.
Bar-Yosef felt that the sediment layers and micro-mammal remains at Qafzeh indicated that Qafzeh's human remains were older than Kebara's Neanderthal remains and not younger as it was once supposed.
"I had a feeling the deposits in Qafzeh cave were much older," Bar-Yosef said. "The stratification of how things accumulated, it was very clear, according to micro-mammals, that it should be older than Kebara."
Sure enough, after dating the Qafzeh remains with the new technology, they were found to be 92,000 years old. With early modern human remains in the region predating the Neanderthal remains, it became apparent that Neanderthals couldn't be human ancestors and were instead contemporaries.
That discovery shook up the prevailing scientific view of the time that Neanderthals were direct human ancestors and grandfathers of Cro-Magnons on the human family tree. The remains at Qafzeh proved that Neanderthals and the ancestors of modern humans diverged at some point, with Neanderthals existing at the same time as Cro-Magnons, more akin to cousins of modern humans than grandfathers.
The beginning of the story at Hayonim
From his work at Kebara and Qafzeh, a picture was emerging of early modern humans as the Levant's original occupants. That picture showed that Neanderthals were latecomers, pushing south and east from their native Europe. Bar-Yosef then turned his attention to the beginning of the story, looking for indications of when those early human Cro-Magnons first came from Africa.
To do that, Bar-Yosef and several American, French, and Israeli collaborators turned to Hayonim Cave in the Galilee in 1992. After eight seasons totaling almost a year of fieldwork, they wrapped up their work at Hayonim in 2000. Bar-Yosef said that, though no human remains were found during that work, the cave helped illustrate how those first immigrants from Africa lived.
What they did find - stone tools, fireplaces, plenty of ashes, and huge quantities of small mammal remains, again deposited by barn owls - paints a picture of intermittent human occupation, Bar-Yosef said. The tools and ash show that humans did use the cave, while the large number of small mammal remains show that barn owls ruled the roost for long periods of time, indicating that humans were absent from the cave for those periods.
Together, he said, the clues point to a people who were adept at making advanced stone tools, who were proficient and mobile hunters, and who collected wood to make fire.
"We know today they were all hunters and gatherers, they brought game back into the cave and roasted it. They cracked the bones for marrow," Bar-Yosef said. "Hayonim cave excavations provided us with the story of how humans lived some 250,000 to 150,000 years ago and produced the only rich assemblage of animal remains from that period in the Middle East."
Though his work has been revealing about the Levant's prehistory, it leaves unanswered the question of what happened more recently, during that Upper Paleolithic revolution when our Cro-Magnon ancestors began to multiply and Neanderthals began to decline.
Though some believe the Neanderthals and Cro-Magnons interbred until the two populations were indistinguishable, Bar-Yosef thinks the warlike traits of people today give evidence of a different Neanderthal fate. Bar-Yosef thinks Neanderthals were either killed by Cro-Magnons with superior weapons or their populations were isolated by incoming Cro-Magnons and fragmented until, with lower reproductive rates, they died out.
To search for clues to that riddle, Bar-Yosef is continuing work at two sites in the Republic of Georgia, begun in 1996. In Georgia, Bar-Yosef is exploring sites in the Caucasus Mountains with Georgian, Israeli, and American colleagues, looking for evidence of the route early humans took into Europe. Many believe they crossed from Turkey to Southeastern Europe, but they also have traveled along the Black Sea's eastern shores, over the Caucasus, and then west into eastern Europe.
By examining those sites, he is also looking for clues as to how modern humans came to dominate Europe. The Caucasus Mountains were an area where Neanderthals were able to exist longer than many other places, so perhaps clues to their demise exist there also.
"What we're trying to find out is when did modern humans come out of Africa and did modern human traits spread by slow diffusion or rapid migration," Bar-Yosef said.
quote:Originally posted by Troll Patrol aka Ish Gebor:
quote:Originally posted by xyyman: I wish some you brothas would slow down on the picture spamming and knee jerk reaction. PLEASE!!!! First read the paper, 2nd understand it. I guess some of us have our strengths.
This paper is as ground breaking as the recent Shriver et al paper on the Cape Verde. Maybe the black greek (herodotus) over at ESR will read it and would stop citing 15 year old outdated studies. HGDP and HAPMAP, GENOGRAPHIC Project as I said before is go to change the landscape and age old racialist beliefs. I will post on it on ESR. As I said – there are no European genes. This paper is in agreement with that Shriver 2013 paper. Infact it cites the Norton/Kittles paper which some of you may know the connection. Shriver was also the co-author on that one. He was Norton’s boss. Kivislid and Villems are the big dog on this one. I respect Kivislid work. See Dhoxie…I like some white people. Some researchesr try to remain honorable/honest with data they disclosed. They try not to falisfy data. Instead they may keep it hidden in Supplementals or spin BS with the data. READ THE STUDY!!!!!!!
In the case the pictures were especially important as these motivated the studies being propelled.
You aren't the only reader, here. Some readers need more explanation to the story.
translation:
Troll can't explain how he and Mike's knee jerk picture spams relate to the article
doesn't even relaize Mike said the article was quote " lies and Bullsh1t"
go ahead try to save your pride now, call me some names
A knee jerk in your stomach.
Let's see, what pseudo wiki site you're going to use this time " as a rebuttal"?
Africa: Continent of Origins
This lecture was delivered by Dr. Ian Tattersall at The Metropolitan Museum of Art on the occasion of the symposium "Genesis: Exploration of Origins" on March 7, 2003. This symposium was held in conjunction with the special exhibition, "Genesis: Ideas of Origin in African Sculpture," and was made possible through the support of The Ford Foundation.
quote:At about 40,000 years ago, however, Homo sapiens, in the form of the Cro-Magnons, began trickling into Europe, probably from an initially African place of origin.
[...]
It was brought with them by the Cro-Magnons, whose new qualities had emerged elsewhere. Probably this was in Africa, for it is from this continent that we have not just the first suggestions of the emergence of modern anatomical structure, but of modern behaviors as well.
[...]
The most remarkable early evidence of symbolic activity in Africa comes in the form of the recent find of engraved ochre plaques, such as this one, from Blombos Cave on the southern coast of Africa (Fig. 10). This is an unequivocally symbolic object, even if we cannot directly discern the significance of the geometric design that the plaque bears; and it is dated to around 70,000 years ago, over 30,000 years before anything equivalent is found in Europe.
To evidence such as this can be added suggestions of a symbolic organization of space at the site of Klasies River Mouth (Fig. 11), also near the southern tip of Africa, at over 100,000 years ago. Pierced shells, with the strong implication of stringing for body ornamentation, are known from Porc-Epic Cave in Ethiopia at around 70,000 years ago. Bone tools of the kind introduced much later to Europe by the Cro-Magnons, are found at the Congolese site of Katanda, dated to perhaps 80,000 years ago. Blade tool industries, again formerly associated principally with the Cro-Magnons, are found at least sporadically at sites in Africa that date to as much as a quarter of a million years ago. Also in the economic/technological realm, such activities as flint-mining, pigment-processing and long-distance trade in useful materials are documented in Africa up to about 100,000 years ago. These and other early African innovations are reviewed by McBrearty and Brooks (2000).
quote:Originally posted by Troll Patrol aka Ish Gebor:
What Mike stated was that during the Pleistocene Europe was inhabited by African like people/ Homo Sapiens Sapiens. Which is correct. However, the particular study I've posted is about the Holocene.
The first Europeans came from Central Asia, they may have dark skin nobody knows but they had African looking features
They came from Central Asia went across Russia and entered into Europe. After arriving in Europe around 35Kya They fvcked some Neaderthals and their skin also lightened, features became narrower. It's called evolutionary adaptation. Look into it,SLC24A5
Posts: 42918 | From: , | Registered: Jan 2010
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For the newbies to summarize: 1. What they are trying to work out in one paragraph is determine the y-DNA haplogroup that spread the derived SLC24A5 through out Eurasia. The could not, so they concluded it occurred BEFORE AMH left Africa…just as Shriver concluded. Why? Because all SSA groups including the San and pygmies carry the derived SLC24A5. BTW “resequencing” means they repeated the tests. Seems like they did not trust the initial results. LOL! But they got the exact same result. LOL! 2. Derived SLC45A2(rs1426654-A allele) although has higher frequency in Europe and S Asia the diversity, meaning age, is higher in Africa and East Asia. The “underived/ancestral” is found mostly in Africa and East Asia. However the derived is also found there. 3. SSA groups like the Bantu, San and Pygmy have the most amount of “novel allele” of the derived SLC24A5. More than Europe and Asia combined!!!!! What is fascinating is the two oldest population in Africa carry the derived SLC24A5!!! Proving yet again light skin is ancestral. 4. Even the cherished and worshiped white skin is NOT European but African in origin. It is because of blackness.we became human. 5. What is interesting also is the Tunisian/Mazabs, Negev Bedouins groups with the highest percentage of SSA African Haplogroups have a higher frequency of SLC24A5.
Will post entire critique on ESR.
-------------------- Without data you are just another person with an opinion - Deming Posts: 12143 | From: When you have eliminated the impossible, whatever remains, however improbable | Registered: Jun 2007
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^^^ like I said Mike flushed down the toilet, wake up TP, don't you understand what he's saying?
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In short. All they are pointing out is SE Asians and West Eurasian have genetic similarities. No shyte!!! They left out the genetic similarity is shared with San and pygmies. The question is who did they get it from? Answer – Africans!!! Both groups got it from Africans. Both the ancestral and derived mutation is found in Africa. The “derived” has highest diversity, most novel and most ancient combination IN Africa. And of all population the San and pygmies!!!. Interestingly only one group of pygmies not the other has the genotype. Of course the Bantus and other groups have the novel derived SLC24A5. The power of HGDP, HAP-Map etc. selective sampling is a thing of the past.
-------------------- Without data you are just another person with an opinion - Deming Posts: 12143 | From: When you have eliminated the impossible, whatever remains, however improbable | Registered: Jun 2007
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quote:Originally posted by Troll Patrol aka Ish Gebor:
What Mike stated was that during the Pleistocene Europe was inhabited by African like people/ Homo Sapiens Sapiens. Which is correct. However, the particular study I've posted is about the Holocene.
The first Europeans came from Central Asia, they may have dark skin nobody knows but they had African looking features
They came from Central Asia went across Russia and entered into Europe. After arriving in Europe around 35Kya They fvcked some Neaderthals and their skin also lightened, features became narrower. It's called evolutionary adaptation. Look into it,SLC24A5
Are you really this dumb?
I've posted multiple sources. Still you babble your usual rant? lol
I have touched all the topics including SLC24A5. I cited directly from sources.
quote: These results argue for an independent evolution of lighter skin in European and East Asian populations. To further test the hypothesis that SLC24A5 has been shaped by positive directional selection in European (but not East Asian) populations we sequenced 4.8 kb of SLC24A5 spanning a 20 kb region in a geographically diverse panel of human populations representing Europe, Asia, Africa, and the Americas.
--Patterns of sequence variation in the human pigmentation candidate gene SLC24A5. H. Norton, M. Hammer. ARL-Biotechnology, Univ Arizona, Tucson, AZ.
quote:Originally posted by xyyman: In short. All they are pointing out is SE Asians and West Eurasian have genetic similarities. No shyte!!! They left out the genetic similarity is shared with San and pygmies. The question is who did they get it from? Answer – Africans!!! Both groups got it from Africans. Both the ancestral and derived mutation is found in Africa. The “derived” has highest diversity, most novel and most ancient combination IN Africa. And of all population the San and pygmies!!!. Interestingly only one group of pygmies not the other has the genotype. Of course the Bantus and other groups have the novel derived SLC24A5. The power of HGDP, HAP-Map etc. selective sampling is a thing of the past.
Yes, and this is what I have shown with multiple papers, which I have cited as backup material.
Not just as some selfopiniated suggestion.
Posts: 22234 | From: האם אינכם כילדי הכרית אלי בני ישראל | Registered: Nov 2010
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I need become more familiar with using Hap-map. I know we spoke about that in the past. I still haven't got around to it.
-------------------- Without data you are just another person with an opinion - Deming Posts: 12143 | From: When you have eliminated the impossible, whatever remains, however improbable | Registered: Jun 2007
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quote:Originally posted by xyyman: I need become more familiar with using Hap-map. I know we spoke about that in the past. I still haven't got around to it.
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