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Digitalseal
Sunday, June 4th, 2006, 03:59 PM
They are often group with us, Normally because of their extreme Europid feature.

But genetic maps show that they are more related to the other Sub-Saharan African groups, but I think that's mostly because of recent mixture.

So, is it known biologically how much Europid blood the Aethiopid peoples have?

Agrippa
Sunday, June 4th, 2006, 04:06 PM
They are often group with us, Normally because of their extreme Europid feature.

But genetic maps show that they are more related to the other Sub-Saharan African groups, but I think that's mostly because of recent mixture.

So, is it known biologically how much Europid blood the Aethiopid peoples have?

Thats a very interesting and complicated issue. I think the best way to describe the typical Aethiopids is, from a genetic standpoint:
There was an original population which was neither typical Negrid nor Europid and into this genpool was both Europid and Negrid proper (Nilotic and Bantu) admixture coming.

The result is in any case a racial type which should be considered a 'contact race' which is predominantely Negroid (not Negrid in the narrower sense). There are different opinions on that, f.e. Baker saw them as being Europid, others simply put them in the Negrid category, again others said they are just the result of mixture, whats too simplistic too. In every case there was local evolution, selection being involved which produced a quite distinctive and relatively stable form.
Especially in Eritrea and some ethnic groups like the Amhara more recent, direct Europid admixture is obvious, whereas in some basic Aethiopids we can really speak of a stabilised contact race with a character on its own.

From the genetic standpoint a lot depends on whether you consider certain haplogroups being Europid, Negrid or neither (just East African/Aethiopid) and whether they can be put in any of this categories anyway (since they could be older - of undifferentiated sapiens lines).

Galaico
Sunday, June 4th, 2006, 04:12 PM
Well genetically they are in some point between Europids and Negrids.

In the Y-lines, they share about 60% of Neolithic Europid haplotypes: ~55% E3b, and ~5% J. The rest is sub-Saharan.

In the mt-lines, they share about ~66% of sub-Saharan haplotypes, ~25% of Europid haplotypes, and ~9% of South Asian (Indian?) haplotypes.

I suppose that during the Neolithic, some agriculturalists from the Middle East or Northern Egypt, moved to East Africa where they mixed up with the local population.

Agrippa
Sunday, June 4th, 2006, 04:20 PM
Thats a good perspective on the 'problem', it was posted on Dodona some time ago:



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Apportionment of individuals to clusters, on the basis of 16 chromosome 1 microsatellites and 23 X-linked microsatellites

(bar graphs added to original fig.)
http://tinypic.com/e88tgn.gif
"The apportionment of individuals (the average per-individual proportion of ancestry) from each of the eight populations into the four STRUCTURE-defined clusters (Table 2) broadly corresponds to four geographical areas: Western Eurasia, Sub-Saharan Africa, China and New Guinea. Notably, 62% of the Ethiopians fall in the first cluster, which encompasses the majority of the Jews, Norwegians and Armenians, indicating that placement of these individuals in a ‘Black’ cluster would be an inaccurate reflection of the genetic structure. Only 24% of the Ethiopians are placed in the cluster with the Bantu and most of the Afro-Caribbeans...."
(J.F. Wilson et al. Nature Genetics 29:265-269, 2001)

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Short Tandem-Repeat Polymorphism/Alu Haplotype Variation at the PLAT Locus: Implications for Modern Human Origins
http://www.journals.uchicago.edu/AJHG/journal/issues/v67n4/001733/001733.html

(labels, colors added)
http://tinypic.com/e8u7w7.gif

"The most distinct separation is between African and non-African populations. The northeastern-African—that is, the Ethiopian and Somali—populations are located centrally between sub-Saharan African and non-African populations."

(S. A. Tishkoff et al., Am. J. Hum. Genet., 67:901-925, 2000)

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Ethiopia: between Sub-Saharan Africa and Western Eurasia

Lovell et al., Annals of Human Genetics (2005) 69,275–287

8kb segment of the X-chromosome

(color coding added)
http://tinypic.com/dxifrb.gif

"Certainly our data are not incompatible with the argument from Tishkoff et al. (1996) that an element of the contemporary Ethiopian population may be descendants of the ancestral population that spawned the migration out of Africa. We also argue, however, that in addition to this early bottleneck event, later periods of admixture have played a major role in shaping the gene pool of Ethiopia, and its populations display both Eurasian and Sub-Saharan genetic influences."

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Cavalli-Sforza et al., Africa PC plot
(The History and Geography of Human Genes, Princeton University Press, 1994)
http://tinypic.com/e88vhi.gif

neighbor-joining network (computed from genetic distances in table 3.6.1, HGHG)
http://tinypic.com/e8u7x0.gif

Neighbor-joining network of world populations (from data in Table 2.3.1A, HGHG, p.174).
http://tinypic.com/e8u80z.gif

"In summary, the information available on individual groups in Ethiopia and North Africa is fairly limited but sufficient to show that they are all separate from sub-Saharan Africans and that North Africans and East Africans (Ethiopian and neighbors) are also clearly separate."
(Cavalli-Sforza et al., HGHG, p.174)

the next tree (UPGMA) is not very reliable at the individual population level, but the general pattern is clear: Ethiopians and neighbors (Beja, N. Sudan, Cushitic, Tigray, Baria, Amhara, but not Somali) cluster with North Africans before other sub-Saharans.

(cluster labels added)
http://tinypic.com/e88vuo.gif



Y chromosome (Eth = Ethiopians)

http://www.journals.uchicago.edu/AJHG/journal/issues/v61n5/970152/fg2.gif

"Non sub-Saharan African samples are all grouped together...with...the Ethiopian Amharic sample. Ethiopians are not statistically differentiated from the Egyptian and Tunisian samples, in agreement with their linguistic affiliation with the Afro-Asiatic family."
(Poloni et al., Am J Hum Genet, 1997)

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(Eth = Ethiopians, EtJ = Ethiopian Jews)
http://www.pnas.org/content/vol97/issue12/images/medium/pq1001159002.gif
(Hammer et al., Proc Natl Acad Sci, 2000)

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Craniometry, CL Brace
MDS plot generated from (unsquared) Mahalanobis distances
http://tinypic.com/b7xnrs.jpg

"When the nonadaptive aspects of craniofacial configuration are the basis for assessment, the Somalis cluster with Europeans before showing a tie with the people of West Africa or the Congo Basin."
(Brace et al., Yearbook of Physical Anthropology, 1993)

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Sanchez et al. (2005)
Euro J Hum Genet

"The data suggest that the male Somali population is a branch of the East African population -- closely related to the Oromos in Ethiopia and North Kenya -- with predominant E3b1 cluster gamma lineages that were introduced into the Somali population 4000-5000 years ago, and that the Somali male population has approximately 15% Y chromosomes from Eurasia and approximately 5% from sub-Saharan Africa.

[ . . . ]

"East Africans are more related to Eurasians than to other African populations."

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"The occurrence of E*5 212 and E*5 204 alleles in two populations of the Mediterranean basin (Turkey and Italy) but not in West Africans can be explained by taking into account that the Ethiopian gene pool was estimated to be >40% of Caucasoid derivation (Cavalli-Sforza et al. 1994). In addition, more recent phylogenetic analysis based on classical protein polymorphism (Tartaglia et al. 1996) and Y-chromosome sequence variation (Underhill et al. 2000) showed that Ethiopians appear to be distinct from Africans and more closely associated with populations of the Mediterranean basin."

(Scacchi et al., Hum Biol, 2003)

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"The present composition of the Ethiopian population is the result of a complex and extensive intermixing of different peoples of North African, Near and Middle Eastern, and south-Saharan origin. The two main groups inhabiting the country are the Amhara, descended from Arabian conquerors, and the Oromo, the most important group among the Cushitic people. ... The genetic distance analysis showed the separation between African and non-African populations, with the Amhara and Oromo located in an intermediate position."

(De Stefano et al., Ann Hum Biol, 2002)

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"On the basis of historical, linguistic, and genetic data, it has been suggested that the Ethiopian population has been strongly affected by Caucasoid migrations since Neolithic times. On the basis of autosomal polymorphic loci, it has been estimated that 60% of the Ethiopian gene pool has an African origin, whereas ~40% is of Caucasoid derivation.... Our Ethiopian sample also lacks the sY81-G allele, which was associated with 86% and 69% of Senegalese and mixed-African YAP+ chromosomes, respectively. This suggests that male-mediated gene flow from Niger-Congo speakers to the Ethiopian population was probably very limited ... Caucasoid gene flow into the Ethiopian gene pool occurred predominantly through males. Conversely, the Niger-Congo contribution to the Ethiopian population occurred mainly through females."
(Passarino et al., Am J Hum Genet, 1998)

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"Somali, as a representative East African population, seem to have experienced a detectable amount of Caucasoid maternal influence"
[Comas et al., Eur J Hum Genet, 1999)

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