posted
I think al-Takruri already addressed these two studies, by to re-emphasize so important points, these two studies are basically outdated and give inaccurate results based on the methodology and interpretation used by the authors. First the CL Fox study on Nubians:
mtDNA analysis in ancient Nubians supports the existence of gene flow between sub-Sahara and North Africa in the Nile valley
"Abstract:
The Hpal (np3,592) mitochondrial DNA marker is a selectively neutral mutation that is very common in sub-Saharan Africa and is almost absent in North African and European populations. It has been screened in a Meroitic sample from ancient Nubia through PCR amplification and posterior enzyme digestion, to evaluate the sub-Saharan genetic influences in this population. From 29 individuals analysed, only 15 yield positive amplifications, four of them (26·7%) displaying the sub-Saharan African marker. Hpa I (np3,592) marker is present in the sub-Saharan populations at a frequency of 68·7 on average. Thus, the frequency of genes from this area in the Merotic Nubian population can be estimated at around 39% (with a confidence interval from 22% to 55%). The frequency obtained fits in a south-north decreasing gradient of Hpa I (np3,592) along the African continent. Results suggest that morphological changes observed historically in the Nubian populations are more likely to be due to the existence of south-north gene flow through the Nile Valley than to in-situ evolution.
And now Krings et al study:
mtDNA Analysis of Nile River Valley Populations: A Genetic Corridor or a Barrier to Migration?
To assess the extent to which the Nile River Valley has been a corridor for human migrations between Egypt and sub-Saharan Africa, we analyzed mtDNA variation in 224 individuals from various locations along the river. Sequences of the first hypervariable segment (HV1) of the mtDNA control region and a polymorphic HpaI site at position 3592 allowed us to designate each mtDNA as being of "northern" or "southern" affiliation. Proportions of northern and southern mtDNA differed significantly between Egypt, Nubia, and the southern Sudan. At slowly evolving sites within HV1, northern-mtDNA diversity was highest in Egypt and lowest in the southern Sudan, and southern-mtDNA diversity was highest in the southern Sudan and lowest in Egypt, indicating that migrations had occurred bidirectionally along the Nile River Valley. Egypt and Nubia have low and similar amounts of divergence for both mtDNA types, which is consistent with historical evidence for long-term interactions between Egypt and Nubia. Spatial autocorrelation analysis demonstrates a smooth gradient of decreasing genetic similarity of mtDNA types as geographic distance between sampling localities increases, strongly suggesting gene flow along the Nile, with no evident barriers. We conclude that these migrations probably occurred within the past few hundred to few thousand years and that the migration from north to south was either earlier or lesser in the extent of gene flow than the migration from south to north.
As we can see in both these studies the author are using markers that have HpaI site at position 3592[which codifies L1 and L2 African mtDNA haplogroups] as the sole criterion for designating markers as "sub-Saharan"["southern haplotypes in Krings et al study]. Any haplotypes lacking HpaI site at position 3592 are erroneously taken to be of non-sub Saharan origin["northern haplotypes in Krings et al study].
It is now known that African macrohaplogroup L3[which includes all so-called "Eurasian" haplogroups] also lack HpaI site at position 3592, therefore the two above studies are inaccurate. Perhaps the author's studies predated all existing knowledge about L3 or either they totally ignored the possibility that some of these haplotypes lacking HpaI site at position 3592 are of African origin. In a study by Chen et al in 1995, this posibility was already raised and pointed out:
"However, although we did not observe haplotypes lacking the 3592 HpaI site in the Pygmies, haplotypes lacking the 3592 HpaI site are not limited to Senegalese populations. These haplotypes have been described in 36% of the Bamileke from Cameroon (Scozzari et al. 1994), 12% of the Khoisan populations from Namibia (Soodyall and Jenkins 1992), and 23% - 89% of several Bantu-speaking populations from southern Africa (Johnson et al. 1983; Soodyall and Jenkins 1993). The finding of mtDNAs without the 3592 HpaI site in sub-Saharan populations, which are unlikely to be genetically admixed with European populations, suggests that at least some of the mtDNAs lacking the 3592 HpaI site in the Senegalese arose in Africa and are not the product of genetic admixture with populations from northern Africa, Europe, or Asia. Because of their widespread distribution in sub-Saharan populations, it is most likely that these mtDNAs have an ancient African origin. An African origin of the mtDNAs without the 3592 HpaI site, their similarity to European and Asian mtDNAs, and the absence of mtDNAs defined by the HpaI site at np 3592 in non-African populations, appear to suggest that African mtDNAs without the 3592 HpaI were the only mtDNAs that were carried from Africa by the Homo sapiens sapiens migrations, which ultimately gave rise to modern non-African populations."
Am. J. Hum. Genet. 57:133-149, 1995
Analysis of mtDNA Variation in African Populations Reveals the Most Ancient of All Human Continent-Specific Haplogroups
Any idiots still invoking the myth that ancient Nubians were significantly mixed need to get with the program and read more updated studies
Posts: 2596 | From: Vicksburg | Registered: Feb 2006
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posted
In fairness to Krings et al, one of their conclusions ("Spatial autocorrelation analysis demonstrates a smooth gradient of decreasing genetic similarity of mtDNA types as geographic distance between sampling localities increases, strongly suggesting gene flow along the Nile, with no evident barriers") does suggest that the Nile Valley was a corridor facilitating gene flow between "North" and "Sub-Sahara" Africa---thus, the "North African" position of Nile Valley civilizations cannot be used to prove their non-blackness, since they weren't really that isolated from sub-Saharan populations.
I think al-Takruri already addressed these two studies,...
Yeah, I recall the posts in question, and this is what I had to say about it then [the entire recapitulation below is a clickable link to the original discussion]:
quote: Originally posted by alTakruri:
Assignment of mtDNA was by a majority of those three loci, 2 out of 3 or 3 out of 3. The report holds to this classification methodology even though a 2/3 class-by-site could contradict full mtDNA database classification. For instance, one of the northern by 2/3 site majority samples was found to be identical to two Songhai and two Kikuyu when full sequencing was employed. Nonetheless it remained as Eurasian! This was so because the weight for sub-Saharan inclusion relied on the presense of HpaI since it's proposed to be of single sub-Saharan origin. In this we can see the makeover of the old physical anthropology's "true negro" myth carried over into the new population genetics anthropology.
...But what do we know of L3 based lineages, do they all have what the authors call?...
In addition, it has been proposed that the HpaI site at 3592 has a single origin in sub-Saharan Africa
Would M1 for instance have this site detected as positive?…
In relation to this question, we have:
The main sub-Saharan African haplotypes, thus, are characterized by a combination of 10394DdeI(+)/10397AluI(-)/3592HpaI(+) markers (haplogroup L, comprising the LI and L2 lineages) (Chen et al. 1995, 2000). A less frequent group of haplotypes lacks the African-specific 3592 HpaI marker [10394DdeI(+)/ 10397AluI(-)/3592HpaI(-)] (Chen et al. 1995, 2000) and has been designated as haplogroup L3 (Watson et al. 1997). A minority of African haplotypes (2.3% of Africans) lack all three of these mutations [10394DdeI(-)/10397AluI(-)/ 3592HpalI(-)]. Some align with the European lineage U (Chen et al. 2000), but a number of the mtDNAs belong to branches of the African haplogroup L3, itself derived from African haplogroup L1 (Watson et al 1997). - Clemencia Rodas et al., Mitochondrial DNA studies show asymmetrical Amerindian admixture in Afro-Colombian and Mestizo populations, 2003.
Posts: 1947 | Registered: Sep 2005
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posted
This African mtDNA thing is beginning to unravel for me, especially when viewing the nucleotide sites. When full better sequencing comes out, it will be interesting to see just the true origin of M1 is.
Posts: 2596 | From: Vicksburg | Registered: Feb 2006
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quote:Originally posted by Tyrann0saurus: In fairness to Krings et al, one of their conclusions ("Spatial autocorrelation analysis demonstrates a smooth gradient of decreasing genetic similarity of mtDNA types as geographic distance between sampling localities increases, strongly suggesting gene flow along the Nile, with no evident barriers") does suggest that the Nile Valley was a corridor facilitating gene flow between "North" and "Sub-Sahara" Africa---thus, the "North African" position of Nile Valley civilizations cannot be used to prove their non-blackness, since they weren't really that isolated from sub-Saharan populations.
True indeed, there was obviously so interaction between Egypt and Nubia in ancient times, but al-Takruri is right in stating that the authors of the above two studies are using the Hpal (np3,592) mitochondrial DNA marker as a euphemism for "True Negro".
Posts: 2596 | From: Vicksburg | Registered: Feb 2006
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This African mtDNA thing is beginning to unravel for me, especially when viewing the nucleotide sites. When full better sequencing comes out, it will be interesting to see just the true origin of M1 is.
At this point, I don't question the African origin of M1, and by extension, the possibility of such for the *basic* characteristic motifs for the M macro-haplogroup; relevant M discussion link.
I merely brought M1 up, as an example of one of the notable L3 derived lineages in East Africa, extending from the sub-Saharan region to the Northeast end. M1 happens to occur predominantly in Africa. My actually motive was to get the reader to start thinking about the L3 lineage - which is just as African in origin as L1 and L2 lineages, but lack the so-called "African-specific" site. So, the fact that the term "African-specific" was used, might mislead someone to think that the other mtDNA lineages under study couldn't have also been African.
Posts: 1947 | Registered: Sep 2005
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Delimiting African to *Africa specific* is a rhetorical tautology.
By definition nothing that originated in Africa and migrated out of Africa can be AFrica specific. [which appears to be implying exclusively AFrican]
It follows that if you constrict African to African specific - Africa only - then by definition there is *no* African [only] influence on anything that is not African. [only].
To foster such a wish-conclusion seems to be the unconcious purpose of the rhetoric.
Some scholars reflect such a deeply ingrained racism that they are blind to just how obviously twisted their base assumptions are.
Posts: 15202 | Registered: Jun 2004
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quote:Originally posted by Tyrann0saurus: In fairness to Krings et al, one of their conclusions ("Spatial autocorrelation analysis demonstrates a smooth gradient of decreasing genetic similarity of mtDNA types as geographic distance between sampling localities increases, strongly suggesting gene flow along the Nile, with no evident barriers") does suggest that the Nile Valley was a corridor facilitating gene flow between "North" and "Sub-Sahara" Africa---thus, the "North African" position of Nile Valley civilizations cannot be used to prove their non-blackness, since they weren't really that isolated from sub-Saharan populations.
True indeed, there was obviously so interaction between Egypt and Nubia in ancient times, but al-Takruri is right in stating that the authors of the above two studies are using the Hpal (np3,592) mitochondrial DNA marker as a euphemism for "True Negro".
BUMP.
Indeed. That's a good a summary as any. An add-on for the archives:
Posts: 5905 | From: The Hammer | Registered: Aug 2008
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posted
^ Zarahan, I've been noticing your pic displays and graphics in several threads now. Where did you get them? Did you create them yourself? They're very nice, and of course an excellent counter display to all the b.s. propagandists. Posts: 26286 | From: Atlanta, Georgia, USA | Registered: Feb 2005
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quote:Originally posted by Djehuti: ^ Zarahan, I've been noticing your pic displays and graphics in several threads now. Where did you get them? Did you create them yourself? They're very nice, and of course an excellent counter display to all the b.s. propagandists.
Self-created via p-point, nothing fancier. I figured something should be out there for quick reference, reflecting the accurate scholarship and learning here you and other veterans have developed, rather than what you rightly call the 'b.s propagandists' out there. The reputed Brace 'Clines and Clusters' diagram is a case in point. References embedded for people to see for themselves. ne more for the archives:
Posts: 5905 | From: The Hammer | Registered: Aug 2008
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posted
^ Well, as I said your graphics are an excellent display and a breath of fresh air compared to those of b.s. propagandists such as Marc Washington. All you need now are actual pictures of ancient depictions and Nile Valley peoples and you are totally set.
Posts: 26286 | From: Atlanta, Georgia, USA | Registered: Feb 2005
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posted
Indeed those graphics are very refreshing for this forum. Maybe as we all feed more information into the forum, zaharan's graphics can enhance the discussions for those who still don't understand whats being said.
Posts: 2596 | From: Vicksburg | Registered: Feb 2006
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