posted
European Journal of Human Genetics advance online publication 6 January 2010; doi: 10.1038/ejhg.2009.231
Human Y chromosome haplogroup R-V88: a paternal genetic record of early mid Holocene trans-Saharan connections and the spread of Chadic languages
Fulvio Cruciani et al.
Although human Y chromosomes belonging to haplogroup R1b are quite rare in Africa, being found mainly in Asia and Europe, a group of chromosomes within the paragroup R-P25* are found concentrated in the central-western part of the African continent, where they can be detected at frequencies as high as 95%. Phylogenetic evidence and coalescence time estimates suggest that R-P25* chromosomes (or their phylogenetic ancestor) may have been carried to Africa by an Asia-to-Africa back migration in prehistoric times. Here, we describe six new mutations that define the relationships among the African R-P25* Y chromosomes and between these African chromosomes and earlier reported R-P25 Eurasian sub-lineages. The incorporation of these new mutations into a phylogeny of the R1b haplogroup led to the identification of a new clade (R1b1a or R-V88) encompassing all the African R-P25* and about half of the few European/west Asian R-P25* chromosomes. A worldwide phylogeographic analysis of the R1b haplogroup provided strong support to the Asia-to-Africa back-migration hypothesis. The analysis of the distribution of the R-V88 haplogroup in >1800 males from 69 African populations revealed a striking genetic contiguity between the Chadic-speaking peoples from the central Sahel and several other Afroasiatic-speaking groups from North Africa. The R-V88 coalescence time was estimated at 9200–5600 kya, in the early mid Holocene. We suggest that R-V88 is a paternal genetic record of the proposed mid-Holocene migration of proto-Chadic Afroasiatic speakers through the Central Sahara into the Lake Chad Basin, and geomorphological evidence is consistent with this view.
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quote:Originally posted by Evergreen: European Journal of Human Genetics advance online publication 6 January 2010; doi: 10.1038/ejhg.2009.231
Human Y chromosome haplogroup R-V88: a paternal genetic record of early mid Holocene trans-Saharan connections and the spread of Chadic languages
Fulvio Cruciani et al.
The Sahara, covering about one third of the African continent from the Atlantic Ocean to the Red Sea, is the earth's most extensive desert. Over the past thousands of years, the Sahara has undergone dramatic climatic oscillations including arid phases, during which it was largely uninhabitable, and humid episodes, which transformed the desert into a fertile landscape.1 After a hyper-arid period about 23–14.5 kya, the Saharan region experienced a monsoonal moist climate, characterized by increased rainfall.2, 3 During the Holocene Climatic Optimum (about 10–5 kya), a few thousand years after the beginning of the humid period, flora and fauna repopulated the desert, and a mosaic of savannah and woodland became well established throughout much of the Sahara.3 At the same time, the Sahara was home to giant lakes,4 the largest of which, the paleolake Megachad, may have possibly covered an area of at least 400 000 km2, more than the Caspian Sea, the biggest lake on earth today.5 This greening scenario was interrupted by a number of arid episodes, and at about 5–6 kya, the region experienced a rapid onset of dryer conditions. These marked the beginning of a shift towards permanent aridity, with variations in the distribution and timing of these changes between the eastern and central/western Sahara.3 Human–environment interactions in the Sahara have been greatly influenced by these climate fluctuations.1
Close links between climatic variations and prehistoric human occupation of the Sahara during the early mid Holocene (10–5 kya) are documented by archeological6, 7, 8 and paleoanthropological9, 10 evidence. However, genetic studies have been limited and mainly focused on uniparental markers and the role of the Nile basin as a corridor for human movements between northeastern and eastern Africa.11, 12, 13, 14
There have only been a few high-resolution analyses to date regarding the distribution of Y-specific haplogroups in the African continent. The emerging picture indicates a clear differentiation between central/western sub-Saharan and northern African populations. Haplogroup E-DYS271, which accounts for >70% of the Y chromosomes in most of the populations south of the Sahara, is found on an average at a frequency of 2–3% in Northern Africa, whereas haplogroups J-M304, E-M81, and E-M78, which on the whole account for 50–90% of the northern African male-specific region of the Y chromosome (MSY) gene pool, have been only rarely observed in west/central sub-Saharan Africa.12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25
A group of chromosomes of potential interest to past trans-Saharan connections is the paragroup R1b1* (R-P25*). Cruciani et al18 found this paragroup (at that time defined as haplogroup 117, or R-M173*(xSRY10831, M18, M73, M269)) to be present at high frequencies (up to 95%) in populations from northern Cameroon. The same paragroup was only rarely observed in other sub-Saharan African regions, and not observed at all in western Eurasia.18 Subsequent studies dealing with the MSY diversity in Africa have confirmed the presence of R-P25*(xM269) in northern Cameroon at high frequencies23 and, at lower frequencies (mean 5%, range 0–20%), of R-P25* immediately south of Cameroon, in several populations from Gabon.25 Interestingly, chromosomes of haplogroup R-P25/R-M173, ancestral for M269 as well as for other ‘Eurasian’ downstream markers, have been found to be present in northern Africa (1% in Algeria, 4% in Tunisia, and 2–4% in Egypt).20, 23, 26 The presence of R-P25 Y chromosomes has also been reported in population groups from the Sudan;27 however, as no internal markers were typed, the sub-haplogroup affiliation of these chromosomes remains undefined.
To shed some light on the past demographic processes that determined the present distribution of R-P25* in Africa, we searched for new MSY mutations refining the phylogeny of haplogroup R1b, and surveyed a wide range of African populations (>1800 males from 69 populations) for the presence of the R1b haplogroup. More than 3500 subjects from Europe and Asia were also analyzed for the same haplogroup to obtain a better insight into the Asia-to-Africa back migration associated with this haplogroup.
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quote:Originally posted by Evergreen: [QUOTE]Originally posted by Evergreen: [qb] European Journal of Human Genetics advance online publication 6 January 2010; doi: 10.1038/ejhg.2009.231
Human Y chromosome haplogroup R-V88: a paternal genetic record of early mid Holocene trans-Saharan connections and the spread of Chadic languages
Fulvio Cruciani et al.
We resequenced about 0.15 Mb of the MSY for each of the four R1b subjects and found six new mutations (V7, V8, V35, V45, V69, and V88). The V45 mutation is phylogenetically equivalent to M173. Among the other five mutations, V88 defines a new monophyletic clade (R-V88 or R1b1a), which includes haplogroups R-M18 (R1b1a1, formerly R1b1a), R-V8 (R1b1a2), R-V35 (R1b1a3, further subdivided by the V7 mutation to R1b1a3* and R1b1a3a), and R-V69 (R1b1a4) (Figure 1).
The microsatellite intermediate variant allele 13.2 at the DYS385 locus B, which has been reported to delineate a new phylogenetic substructure within the human Y chromosome paragroup R1b*,25, 35 was not observed in any of the 106 R1b Y chromosomes analyzed here. Therefore, the phylogenetic relationships between this marker and the new mutations reported here remain to be defined.
In total, 997 chromosomes belonging to the haplogroup R1b were found. The paragroup R-M343*, earlier reported in a single subject from Turkey,28 was not observed. The overall scenario was characterized by a strong inter-continental differentiation (Table 1). All the African R1b chromosomes, with the exception of one eastern- and a few northern-African R-M269 chromosomes, turned out to belong to the haplogroup R-V88. About one third of the African R-V88 chromosomes carried mutation V69, which was not observed outside Africa. The large majority of R1b chromosomes from western Eurasia carried, as expected, the M269 mutation; only five R-V88 chromosomes were observed, three of which carried distinctive mutations (M18, V35, and V7). The rare R1b chromosomes observed in Asia were either R-M73 or R-M269. The R-P25* paragroup was only found in five subjects from Europe (3), western Asia (1), and eastern Asia (1) (Table 1).
According to the phylogeography of macro-haplogroup K-M9 (which contains haplogroup R1b), an ancient Asia-to-Africa back migration has been hypothesized to explain the puzzling presence of R-P25* in sub-Saharan Africa.18 This hypothesis is strongly supported by the present data. In the revised Y chromosome phylogeny, there are 119 lineages in the macro-haplogroup K-M9 (which includes haplogroups K1-K4 and L to T).31 Of these lineages, only two have been observed in sub-Saharan Africa at appreciable frequencies: T-M7018, 41, 42 and R-V88 (this study). Both haplogroups have also been observed in Europe and western Asia (Refs 42,43 and this study). If the presence of R1b chromosomes in Africa was not because of a back migration, we would have to assume that all the mutations that connect M9 with V88 in the MSY phylogeny (>50 mutations) originated in Africa. Under this scenario, we should assume that all the K-M9 lineages that are now found outside sub-Saharan Africa have survived extinction, whereas those which should have accumulated in Africa are now extinct (with the exception of T-M70 and R-V88) and this is an unlikely scenario. We obtained the time estimate of the Asia-to-Africa back migration by using the variation associated with seven tetranucleotide microsatellites (Supplementary Table 2) and the ASD method.36 As an upper limit, we used the coalescence time of the R-M343/P25 haplogroup (12.9 ky, 95% CI=11.6–14.3 ky, under a conservative scenario of constant population size), which, on the basis of the accumulated nucleotide and microsatellite diversity (Table 1; Figure 2), most likely originated outside Africa. The coalescence time of the seemingly African-specific haplogroup R-V69 (6.0 ky, 95% CI=4.2–8.2 ky, under the hypothesis of an expanding population) was used as a lower limit.
Within Africa, the highest frequencies of the R-V88 haplogroup (and its commonest sub-clade, R-V69) were observed in the central Sahel (northern Cameroon, northern Nigeria, Chad, and Niger) (Table 1; Figure 3). Immediately south of this region (southern Cameroon and southern Nigeria), frequencies drastically dropped to 0.0–4.8%. The central Sahel is characterized by a strong linguistic fragmentation with populations speaking languages belonging to three of the four linguistic families of Africa (Afroasiatic, Niger-Congo, and Nilo-Saharan). When the linguistic affiliation of the populations from the central Sahel was also taken into account, a clear-cut divide was observed between those speaking Afroasiatic languages (including the Berber-speaking Tuareg, the Semitic Arab Shuwa, and Chadic-speaking populations from northern Cameroon) and the other populations (Mann–Whitney test P=1.4 × 10−3), with Chadic-speaking populations mostly contributing to this difference. It is worth noting that, if the finding of 20% R-V88 chromosomes among the Hausa (Table 1) is representative, this population, encompassing by far more people than all other Chadic speakers,44 also encompasses the highest absolute number of V88 carriers.
In contrast to prior studies on nuclear (mostly autosomal) ins/del and microsatellite markers,45 the Chadic are distinguished from the Nilo-Saharan-speaking populations at the Y chromosome variation level (Table 1; Supplementary Table 3). Repeated assimilations of Nilo-Saharan females over generations may account for these conflicting signals. Among the Niger-Congo-speaking populations, the frequency of the haplogroup R-V88 ranged between 0.0 and 66.7%. Outside central Africa, haplogroup R-V88 was only observed in Afroasiatic-speaking populations from northern Africa, with frequencies ranging from 0.3% in Morocco, to 3.0% in Algeria, and to 11.5% in Egypt, where a particularly high frequency (26.9%) was observed among the Berbers from the Siwa Oasis. Although the presence of the haplogroup R-V88 at non-negligible frequencies in some Niger-Congo-speaking populations from the central Sahel can be accounted for by Chadic admixture favored by geographic contiguity, the presence of this haplogroup both in northern Africa and the central Sahel is especially intriguing given that >1500 km across the Sahara separate the two regions. The expansion time for the haplogroup R-V88 in Africa, under two different population models (see Materials and methods), was found to be 9.2–5.6 ky (95% CI=7.6–10.8 ky and 4.7–6.6 ky, respectively).
Diverse hypotheses have been proposed to explain the process by which proto-Chadic speakers arrived to the Lake Chad region. Ehret46 has put forward a model for Afroasiatic languages with a primary division between the Omotic languages of Ethiopia and an Erythraean subgroup. This, in turn, has been subdivided into Cushitic and North Erythraean, the latter including Berber, Semitic, Ancient Egyptian, and Chadic. In his opinion, around 7000 kya proto-Chadic Afroasiatic speakers may have moved west through the Central Sahara and then farther south into the Lake Chad Basin.47 Blench,48 in turn, suggested that speakers of proto-Cushitic–Chadic language migrated east-to-west from the Middle Nile to the Lake Chad, and recent mtDNA data support this view.49 However, in contrast to the mtDNA, a strong connection between Chadic and other Afroasiatic populations from Northern Africa is revealed by the Y chromosome data. This finding would indicate the trans-Saharan47 a more likely scenario than the inter-Saharan hypothesis,48 at least as far as the male component of gene pool is concerned. In this view, it is tempting to speculate that the Y chromosome haplogroup R-V88 represents a preserved genetic record of gene flow along the same axis as the proposed spread of proto-Chadic languages.47 Indeed, geomorphological evidence4 from the paleolakes that existed in the Sahara during the mid-Holocene indicates that these lakes could have covered an area as large as about 10% of the Sahara, providing an important corridor for human migrations across the region.5
In summary, our data indicate a significant male contribution from northern Africa (and ultimately Asia) to the gene pool of the central Sahel. The trans-Saharan population movements resulting in this genetic pattern would seem to mirror the spread of the proto-Chadic languages, and most likely took place during the early mid Holocene, a period when giant paleolakes may have provided a corridor for human migrations across what is now the Sahara desert.
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quote:Originally posted by Evergreen: [QUOTE]Originally posted by Evergreen: [qb] [QUOTE]Originally posted by Evergreen: [qb] European Journal of Human Genetics advance online publication 6 January 2010; doi: 10.1038/ejhg.2009.231
Human Y chromosome haplogroup R-V88: a paternal genetic record of early mid Holocene trans-Saharan connections and the spread of Chadic languages
Fulvio Cruciani et al.
In summary, our data indicate a significant male contribution from northern Africa (and ultimately Asia) to the gene pool of the central Sahel.
Evergreen Writes:
It's interesting that in Cruciani's study of E1b1b here never made the comment:
In summary, our data indicate a significant male contribution from the Levant (and ultimately Africa) to the gene pool neolithic Europe.Posts: 2007 | From: Washington State | Registered: Oct 2006
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posted
^That's because people like Cruciani would like to have Africans, which Eurocentrists [overt and closet] generally read as synonymous with "sub-Saharan Africans" [whom Eurocentrists seem to have inexplicable beef with], be the recipients of gene flow but not the donors, esp. when it comes to Europeans. This is why he tries to force an argument for African R chromosomes to be "Eurasian" and lower down their age to fit this preconceived dogma, no matter how frivolous and even though known genealogical data suggest otherwise. Recall that Cruciani's 2002 study, where coastal northwest African samples were used, and yet none of them turned out what he then call dubbed as R-M173 chromosomes lacking "any known downstream mutations", which were on the other hand, found only in his sub-Saharan African samples (Cameroon). Even in this renewed attempt, the northwest Africans show negligible to fairly modest Hg R frequencies. So one would have to take it that the *ambiguous* "northern Africa" above must be an allusion to Egypt, yet even the Egyptian sample-records had not measured up to the frequency levels seen in sub-Saharan Africans (particularly around Cameroon). Cruciani's bigger problem is that the African paraphyletic chromosomes are actually more diverse than he wishes they were -- as I noted in another thread of the same topic.
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posted
Has anyone other than Cruciani come up with these "variants" (like V88 or the others he came up with in the E haplogroup)?
It seems Cruciani wants to expunge African demic origins from haplogroups shared by Europeans and Africans. Why don't his variants and clusters within clades show up in haplogroups not shared by Africans and non-Africans?
Has he or any other geneticists even tried to find them in solely extra-African haplogroups? If not, why is no population geneticist interested in going down the road Cruciani is paving?
posted
Nope; just Cruciani. The so-called V88, even according to his own data, is fairly rare outside of the continent, not to mention the unique "V6".
Contrary to Cruciani's mindset, it is not necessary for *all* the sub-clades of K to emerge in Africa, in order for the origin of K-M9 on the continent to be probable. Hg K's most immediate descendants like Hgs T, K1, K2...etc do not form monophyletic branching with respect to one another, but each of them form their own distinctive branch from the ancestral K-M9 node. Nor is it even necessary for the M9 mutation to have emerged in Africa, in order for R to emerge in Africa; humans are not static creatures. All that is needed, is for the P clade to have been present in Africa at some point in time. To my knowledge, P has not been uncovered as a standalone clade [lacking downstream markers] anywhere.
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posted
I looked up Haplogroup R on wiki and found that there are a lot of non African haplogroups haplogroups between the latest African haplogroup (CT??) and the haplogroup that eventually brought about R*
So if I understand it right, ultimately, one of those in between haplotypes came from a non african source to create R* possibly on the African continent
How do you evaluate a haplogroup that arose in one continent, but developed on its own in another continent?
Lets say, if from European specific E3b, a new haplogroup would arise, and this haplogroup would find its way to Africa, how do you evaluate it?
Is it African or European?
If they (scientist) can't even make up their minds about evaluating haplogroups that migrated to Africa once and stayed (east african specific J, north african U6), how do you evaluate a haplogroup that migrated twice?
I looked up Haplogroup R on wiki and found that there are a lot of non African haplogroups haplogroups between the latest African haplogroup (CT??)...
It would be CF and DE [Underhill et al. 2007].
quote: So if I understand it right, ultimately, one of those in between haplotypes came from a non african source to create R* possibly on the African continent
Which one?
quote:
How do you evaluate a haplogroup that arose in one continent, but developed on its own in another continent?
Extrapolation from molecular make up, frequency and distribution patterns.
quote: Lets say, if from European specific E3b, a new haplogroup would arise, and this haplogroup would find its way to Africa, how do you evaluate it?
Is it African or European?
Primarily, it would have to have one-time characteristic UEPs that could only have emerged in Europe, and Europe would also have to host ancestral molecular nodes that are not found in Africa.
quote: If they (scientist) can't even make up their minds about evaluating haplogroups that migrated to Africa once and stayed (east african specific J, north african U6), how do you evaluate a haplogroup that migrated twice?
Kalonji
Again, it comes down to molecular, frequency and distribution patterns. I give theoretical examples herePosts: 7516 | From: Somewhere on Earth | Registered: Jan 2008
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quote: Originally posted by The Explorer: It would be CF and DE [Underhill et al. 2007].
I left DE out because it isn't one of R ancestors, but I didn't know CF was considered African.
quote: Originally posted by The Explorer: Which one?
I don't know which one, I think we can only make educated guesses until we sample pre historic skeletons from both areas, Africa and Eurasia. For example, the sampled Cro magnon turned out to be N, and no L. If this lack of L in these Cro Magnon is representative for all Cro magnon and contemporous non Africans, this would mean that N was already present in Africa when the ancestors of the Cro Magnon left Africa. It would be hard to make the same case if you would only look at current populations. N carriers in Africa could’ve died off, they could’ve left altogether, a lot of things could’ve happened that can explain the little amounts of N in East Africa. I think the same thing is potentially true for some of R ancestors.
quote: Originally posted by The Explorer: Extrapolation from molecular make up, frequency and distribution patterns.
I should’ve been more clear, I was actually asking from a philosophical standpoint: how you can one evaluate the origins of a haplogroup if it migrates to another continent, and then turns into another haplogroup. Area 1 can claim the haplogroup because it sprung from a haplogroup that they carry, and that there is more affinity between the haplogroups they carry, and the new haplogroup that arose in Area 2, than between the new haplogroup and the other haplogroups that are dominant in area 2. Area 2 can argue that only they carry the specific haplogroup so it should be considered not belonging to area 1. I’ve seen scientist take both attitudes so what I’m asking is, how does science resolve this?
quote: Originally posted by The Explorer: It would be CF and DE [Underhill et al. 2007].
I left DE out because it isn't one of R ancestors, but I didn't know CF was considered African.
It doesn't matter. My comment was to give a very brief but big picture of where the African-based bifurcation points lead off to non-African ancestry.
quote:
I don't know which one, I think we can only make educated guesses until we sample pre historic skeletons from both areas, Africa and Eurasia. For example, the sampled Cro magnon turned out to be N, and no L. If this lack of L in these Cro Magnon is representative for all Cro magnon and contemporous non Africans, this would mean that N was already present in Africa when the ancestors of the Cro Magnon left Africa. It would be hard to make the same case if you would only look at current populations. N carriers in Africa could’ve died off, they could’ve left altogether, a lot of things could’ve happened that can explain the little amounts of N in East Africa. I think the same thing is potentially true for some of R ancestors.
Well, the idea that Cro-Magnon maternal, and it is important to specify who these "Cro-Magnon" samples were -- the Paglicci samples from Italy, not the French-based one, belong to the N macro-haplogroup comes from Caramelli et al. One has to be cautious about these findings; even the analysts here could not tell where the said Cro-Magnon findings placed them in that mtDNA lineage. Some of the markers they invoked, if memory serves me correctly, may not even have been limited to N. I'll have to take another look at it.
quote: I should’ve been more clear, I was actually asking from a philosophical standpoint: how you can one evaluate the origins of a haplogroup if it migrates to another continent, and then turns into another haplogroup. Area 1 can claim the haplogroup because it sprung from a haplogroup that they carry, and that there is more affinity between the haplogroups they carry, and the new haplogroup that arose in Area 2, than between the new haplogroup and the other haplogroups that are dominant in area 2. Area 2 can argue that only they carry the specific haplogroup so it should be considered not belonging to area 1. I’ve seen scientist take both attitudes so what I’m asking is, how does science resolve this?
Kalonji
Yeah, I see what you are saying. Still, the real answer lies in what I said earlier: the molecular, frequency and distribution pattern. Area 1 one can say that the Area 2-specific sub-clade is ultimately indicative of ancestry from Area 1, and in that, Area 1 would be right. Area 2 can turn around and say that the Area 2-specific sub-clade is indicative of migration back into Area 1, and that too would be correct. They are both correct in that, the overall picture is one where the lineage started out in Area 1, moved into Area 2 and then back to Area 1.
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quote: Originally posted by The Explorer: Well, the idea that Cro-Magnon maternal, and it is important to specify who these "Cro-Magnon" samples were -- the Paglicci samples from Italy, not the French-based one,
Why do you make this distinction? Do the French Cro Magnon posess more Cro Magnon-like physical features? Why do you think they didn't start with the French samples, if there was more reason to do so?
quote: One has to be cautious about these findings; even the analysts here could not tell where the said Cro-Magnon findings placed them in that mtDNA lineage. Some of the markers they invoked, if memory serves me correctly, may not even have been limited to N. I'll have to take another look at it.
I agree, thats why I was cautious in the way I made my statement. The truth is, even if the findings are not contaminated, one sample does not speak for other Cro Magnon remains so we still cannot make generalisations about a lack of L in Cro Magnon as a whole. More samples have to be taken from different Cro Magnon skeletal remains. In my opinion, The same is true about R and pre R haplogroups
quote: Yeah, I see what you are saying. Still, the real answer lies in what I said earlier: the molecular, frequency and distribution pattern. Area 1 one can say that the Area 2-specific sub-clade is ultimately indicative of ancestry from Area 1, and in that, Area 1 would be right. Area 2 can turn around and say that the Area 2-specific sub-clade is indicative of migration back into Area 1, and that too would be correct. They are both correct in that, the overall picture is one where the lineage started out in Area 1, moved into Area 2 and then back to Area 1.
Yes, so in your opinion the haplogroup would belong to both areas? The reason why I ask this is because R is one of those haplogroups that migrated back and forth. I was wondering what the implications would be if R* arose in Africa, and how to evaluate, in the face of complex back and forth migrations, to whom the haplogroup belongs. Do you when talking specifically about R* still feel the haplogroup belongs to both areas?
Not that its THAT important to me, I just want a correct way to classify not only paternal R but all haplogroups that were subject to back and forth migrations
Why do you make this distinction? Do the French Cro Magnon posess more Cro Magnon-like physical features? Why do you think they didn't start with the French samples, if there was more reason to do so?
Just to point out the fact that this is not the specimen that was *originally* called the Cro-Magnon, a title which goes to the French-based specimen. Furthermore, there are clearly variant types that have over the years casually been labeled as "Cro-Magnon" [made a thread related to this], and so, the so-called "Cro-Magnon" need not represent a "type". As for going with the Paglicci specimens, well -- I think it had to with immediate accessibility; also, according to Caramelli et al. 2008, their research team was involved in the handling of the retrieval of Paglicci finds right from the excavation stage, which means they can vouch for the authenticity of their DNA findings [i.e. no contaminations]. The French specimen may not necessarily have provided the prospect of such reassurance.
quote:
quote: One has to be cautious about these findings; even the analysts here could not tell where the said Cro-Magnon findings placed them in that mtDNA lineage. Some of the markers they invoked, if memory serves me correctly, may not even have been limited to N. I'll have to take another look at it.
I agree, thats why I was cautious in the way I made my statement. The truth is, even if the findings are not contaminated, one sample does not speak for other Cro Magnon remains so we still cannot make generalisations about a lack of L in Cro Magnon as a whole. More samples have to be taken from different Cro Magnon skeletal remains. In my opinion, The same is true about R and pre R haplogroups
It is not just a matter of contamination that warrants caution in approaching the said DNA finds, but questions around molecular particulars the authors pointed out.
quote:Yes, so in your opinion the haplogroup would belong to both areas? The reason why I ask this is because R is one of those haplogroups that migrated back and forth. I was wondering what the implications would be if R* arose in Africa, and how to evaluate, in the face of complex back and forth migrations, to whom the haplogroup belongs. Do you when talking specifically about R* still feel the haplogroup belongs to both areas?
Well, certain clades belong to certain areas where they are largely confined. I am not entirely certain on where exactly the R clade emerged [though from DNA and distribution patterns it is possible to narrow down the likely candidates], but I don't rule out Africa as a possibility. I've already covered it here and elsewhere, as to why I think that.
I can see why though, many Europeans for ideological reasons would not like the clade to have originated in Africa; I think Cruciani's efforts make this clear.
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quote: Originally posted by The Explorer: Just to point out the fact that this is not the specimen that was *originally* called the Cro-Magnon, a title which goes to the French-based specimen. Furthermore, there are clearly variant types that have over the years casually been labeled as "Cro-Magnon" [made a thread related to this], and so, the so-called "Cro-Magnon" need not represent a "type". As for going with the Paglicci specimens, well -- I think it had to with immediate accessibility; also, according to Caramelli et al. 2008, their research team was involved in the handling of the retrieval of Paglicci finds right from the excavation stage, which means they can vouch for the authenticity of their DNA findings [i.e. no contaminations]. The French specimen may not necessarily have provided the prospect of such reassurance.
ah hah
quote: Well, certain clades belong to certain areas where they are largely confined. I am not entirely certain on where exactly the R clade emerged [though from DNA and distribution patterns it is possible to narrow down the likely candidates], but I don't rule out Africa as a possibility.
I agree
quote:I can see why though, many Europeans for ideological reasons would not like the clade to have originated in Africa; I think Cruciani's efforts make this clear.
Exactly, and just because of that, I hope R* DID originate in Africa. Can't wait to log on to Egyptsearch and see the title of a post along the lines: Conclusive evidence R* arose in Africa
quote:Originally posted by Evergreen: European Journal of Human Genetics advance online publication 6 January 2010; doi: 10.1038/ejhg.2009.231
Human Y chromosome haplogroup R-V88: a paternal genetic record of early mid Holocene trans-Saharan connections and the spread of Chadic languages
Fulvio Cruciani et al.
We suggest that R-V88 is a paternal genetic record of the proposed mid-Holocene migration of proto-Chadic Afroasiatic speakers through the Central Sahara into the Lake Chad Basin, and geomorphological evidence is consistent with this view.
Evergreen Writes:
There are two primary models for the spread of Y-haplogroup J into Africa. One model proposes a neolithic migration into Africa from SW Asia and the other propose small scale movement of J during the neolithic with the main dispersal during the so-called "Arab" conquest.
If R-V88 is indicative of a proto-Chadic migration from mid-Holocene central sahara it is of note that while E1b1b lineages do seem to correlate with R-V88, y-haplogroup J lineages do not. This would favor a late arrival for haplogroup J in Africa (i.e., the "Arab" conquest theory).
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quote:Originally posted by Evergreen: European Journal of Human Genetics advance online publication 6 January 2010; doi: 10.1038/ejhg.2009.231
Human Y chromosome haplogroup R-V88: a paternal genetic record of early mid Holocene trans-Saharan connections and the spread of Chadic languages
Fulvio Cruciani et al.
We suggest that R-V88 is a paternal genetic record of the proposed mid-Holocene migration of proto-Chadic Afroasiatic speakers through the Central Sahara into the Lake Chad Basin, and geomorphological evidence is consistent with this view.
Evergreen Writes:
There are two primary models for the spread of Y-haplogroup J into Africa. One model proposes a neolithic migration into Africa from SW Asia and the other propose small scale movement of J during the neolithic with the main dispersal during the so-called "Arab" conquest.
If R-V88 is indicative of a proto-Chadic migration from mid-Holocene central sahara it is of note that while E1b1b lineages do seem to correlate with R-V88, y-haplogroup J lineages do not. This would favor a late arrival for haplogroup J in Africa (i.e., the "Arab" conquest theory).
By the way, haplogroup E1b1b1a1b(E-V32) also supports the late arrival of haplogroup J lineages in Africa. If haplogroup J nested in the Nile or the Sahara we would expect to see higher frequencies of J lineages among the Somali and Borana and to be co-existant with the back migration of E1b1b1a1b (E-V32) from the mid-Holocene Nile Valley.
Posts: 2007 | From: Washington State | Registered: Oct 2006
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Observation: Horn of Africa populations which have considerable frequencies of the M78 mutation, generally tend to show negligible, if any, Hg R chromosomes. It even has low frequencies in coastal northern Africa, with a gradient that dramatically drops from the Nile Valley and westward from there. The same pattern is observed about the Cruciani's V88 variant. According to this study, at least from what I've read here, V88 chromosomes start to fade in frequency as one leaves the African continent. Only *5* "Eurasian" individuals showed up the V88 marker. One would expect this marker to have visible presence in the European regions around the Mediterranean sea and the so-called "Near East", if it were a primary marker for people who were said to be moving with their "Neolithic agriculture-based subsistence" traditions to new areas. Hg J is found in visible frequencies in these areas. On the other hand, J is negligible, if any at all, found in the central-western African populations bearing the Hg R chromosomes. These same populations which were implicated in considerable frequencies of Hg R, either have been implicated in relatively low levels of E1b1b markers [one of the markers generally implicated in the spread of the Neolithic economy into Europe, esp. the M78 lineage] or none [according to Cruciani's 2002 study for example, the Ouldeme who reported 95% paraphyletic Hg R, reported no M78]. So, there is some degree of co-existence between E1b1b and Hg R in these areas. In this case, the presence of E1b1b may well serve the purpose of partially explaining how the proto-Chadic speakers attained their "Afro-Asiatic" affiliated language phylum. If Hg J and E co-existence is reflective of the spread of the Neolithic agricultural economy, then possible Neolithic spread of Hg R with Hg E would have been migratory event independent from that movement.
Ps - Let's not forget that Cruciani's study does not account for rare R clade diversity in Africa.
Posts: 7516 | From: Somewhere on Earth | Registered: Jan 2008
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^ A big bump up, especially in regards to this silly fiasco of Tut supposedly having R1b lineage!
Posts: 26239 | From: Atlanta, Georgia, USA | Registered: Feb 2005
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