May 12, 2009

Light-pigmented Caucasoids from prehistoric Siberia

This sample was previously tested for Y-chromosome and mtDNA polymorphisms.

The pigmentation-related loci tested can be seen in the labels of my post, which should lead you to some earlier studies on them.

Most individuals were found to be most similar to European than to East Asian or African individuals based on these loci, although some (2 from Andronovo) of them were more similar to East Asians or intermediate (1 from Tagar) between East Asians and Europeans.

Interestingly, 1 of the Andronovo Mongoloids (S07) was previously found to belong to Y chromosome haplogroup C(xC3), while the Caucasoid-Mongoloid individual from Tagar (S32) belonged to haplogroup R1a1.

It should be noted that the use of the term "European individual ancestry" does not mean that these individuals were from Europe, as no test to distinguish between European and Asian Caucasoids was performed, and we know from literary descriptions and occasional archaeological remains about the ancient presence of light-pigmented Caucasoids in Siberia.

From the paper:
The genotype for rs12913832 was obtained for 23 out of the 25 samples, and most had the G/G genotype (n=15), which indicates that at least 60% of ancient specimens were probably blue- or green-eyed individuals. The remaining samples had the A/G (n=5) or A/A (n=3) genotypes, which are predictive of brown eye color phenotype.

International Journal of Legal Medicine doi:10.1007/s00414-009-0348-5

Pigment phenotype and biogeographical ancestry from ancient skeletal remains: inferences from multiplexed autosomal SNP analysis

Caroline Bouakaze et al.


In the present study, a multiplexed genotyping assay for ten single nucleotide polymorphisms (SNPs) located within six pigmentation candidate genes was developed on modern biological samples and applied to DNA retrieved from 25 archeological human remains from southern central Siberia dating from the Bronze and Iron Ages. SNP genotyping was successful for the majority of ancient samples and revealed that most probably had typical European pigment features, i.e., blue or green eye color, light hair color and skin type, and were likely of European individual ancestry. To our knowledge, this study reports for the first time the multiplexed typing of autosomal SNPs on aged and degraded DNA. By providing valuable information on pigment traits of an individual and allowing individual biogeographical ancestry estimation, autosomal SNP typing can improve ancient DNA studies and aid human identification in some forensic casework situations when used to complement conventional molecular markers.



Ebizur said...

Haven't two of the samples of ancient Y-DNA from burials of the Andronovo culture been classified as R1a1, and the other as C(xC3)? Do the two individuals from Andronovo who have been found to cluster with East Asians in the present study both belong to the sample of three individuals from the Andronovo culture whose Y-DNA has been found to belong to R1a1, R1a1, and C(xC3)? If so, then we should have one C(xC3) individual from Andronovo who clusters with East Asians, one R1a1 individual from Andronovo who clusters with East Asians, and one R1a1 individual from Tagar who is intermediate between the East Asian cluster and the European cluster.

Ebizur said...

Isn't it odd that there would be one C(xC3) who clusters with East Asians, one R1a1 who clusters with East Asians, and one R1a1 who clusters with Europeans, all from the same archaeological horizon, i.e. Andronovo? Are the phenotypes of the skeletal remains of humans in Andronovo burials notably heterogeneous?

Dienekes said...

There were three Andronovo individuals with Y-chromosome results (2 R1a1 and 1 C(xC3)). The R1a1's comes up as "European", the C(xC3) as "East Asian".

There are nine Andronovo individuals with autosomal results (this study), two of which come up as "East Asian", and seven as "European".

1 of 8 Tagar individuals is intermediate, and there were 5/6 of them that had R1a1 Y-chromosomes -- the sixth was not determined.

Ebizur said...

Thanks for your clarification of the numbers, Dienekes.

So, you mean that 1/9 Andronovo individuals who have been tested in the present study of autosomal variation belongs to Y-DNA haplogroup C(xC3) and clusters with East Asians, 1/9 Andronovo individuals is a female (or for some other reason has not had the results of a Y-DNA assay reported) and clusters with East Asians, and the remaining 7/9 Andronovo individuals cluster with Europeans, including the two individuals whose Y-DNA has previously been determined to belong to haplogroup R1a1. Is this correct?

Dienekes said...


Polak said...

Looks like there were some long range expansions out of Central Europe during the Bronze Age.

Those Corded Ware R1a1s are certainly related to these guys, and we also have that example of a Scythian mummy being most similar to Poles and Russians in terms of autosomal DNA.

Of course, after getting to Siberia, they took locals for wives, hence the Asian component. One of those Scythian mummies had an Asian specific mtDNA lineage.