July 28, 2005

Pre-Roman Iberian mtDNA

A new study has been published on the ancient DNA of Iberia. Here is a link to several other ancient DNA articles reported previously on this blog:
The most frequent haplogroup is H (52.9%), followed by U (17.6%), J (11.8%), and pre-HV, K and T at the same frequency (5.9%). No samples were found to correspond to other haplogroups that are widely present in the Iberian peninsula populations (Table 7), such as V, X, I or W. The North African U6 subhaplogroup and Sub-Saharan African L lineages are also absent from the ancient Iberians analyzed so far; therefore, the possible entry of U6 lineages prior to the Muslim conquest in the 8th century A.D., as suggested by some authors, remains unproven. However, it is recognized that the sample size is at present too small to exclude any competing hypothesis about a possible North African genetic contribution to the genesis of the Iberian peninsula populations.

This appears to be in general agreement with the recent paper on the origin of African mtDNA in Iberia. The absence of mtDNA haplogroup V, common today in Iberia, is confirmed. Interestingly haplogroup H1, which is a subclade of the frequent haplogroup H was also found in the prehistoric sample. H1 is believed to have originated in Iberia.

Annals of Human Genetics (Early View)

The Genetics of the Pre-Roman Iberian Peninsula: A mtDNA Study of Ancient Iberians

M. L. Sampietro et al.


The Iberians developed a surprisingly sophisticated culture in the Mediterranean coast of the Iberian Peninsula from the 6th century BC until their conquest by the Romans in the 2nd century BC. They spoke and wrote a non-Indo-European language that still cannot be understood; their origins and relationships with other non-Indo-European peoples, like the Etruscans, are unclear, since their funerary practices were based on the cremation of bodies, and therefore anthropology has been unable to approach the study of this people. We have retrieved mitochondrial DNA (mtDNA) from a few of the scarce skeletal remains that have been preserved, some of them belonging to ritualistically executed individuals. The most stringent authentication criteria proposed for ancient DNA, such as independent replication, amino-acid analysis, quantitation of template molecules, multiple extractions and cloning of PCR products, have been followed to obtain reliable sequences from the mtDNA hypervariable region 1 (HVR1), as well as some haplogroup diagnostic SNPs. Phylogeographic analyses show that the haplogroup composition of the ancient Iberians was very similar to that found in modern Iberian Peninsula populations, suggesting a long-term genetic continuity since pre-Roman times. Nonetheless, there is less genetic diversity in the ancient Iberians than is found among modern populations, a fact that could reflect the small population size at the origin of the population sampled, and the heterogenic tribal structure of the Iberian society. Moreover, the Iberians were not especially closely related to the Etruscans, which points to considerable genetic heterogeneity in Pre-Roman Western Europe.


No comments: