The origin of Icelandic mtDNA lineages from haplogroup C

[I2a1a]

Спасибо Валерию Запорожченко за ссылку

The origin of Icelandic mtDNA lineages from haplogroup C

Icelanders are one of the most studied populations in human genetics. The deCODE Genetics genealogical database allows unusually detailed conclusions to be drawn about the population history of the Icelanders. In this study, genetic and genealogical data were combined to make inferences about a rare mtDNA haplotype found in Iceland that belongs to haplogroup C1. While most of the Icelandic mtDNA pool originated in the British Isles or Scandinavia, this haplotype is likely to have a more distant origin, either from East Asians or Native Americans. The goal of the research described in this thesis was twofold. First, we wanted to know its time of entry onto the Icelandic mtDNA pool. In all, 744 individuals were sequenced for their mtDNA control region in this study in addition to the 1538 mtDNA control region sequences available beforehand. Of these 2,266 individuals, seven were haplogroup C1 carriers yielding a population frequency of about 0.3%. The seven Icelandic haplogroup C1 carriers could be traced back to four matrilineal ancestors, born between 1710 and 1740 AD from a limited geographic region. We conclude that a single founding female ancestor gave rise to the Icelandic haplogroup C lineage, who must have arrived sometime between the starting date of the settlement of Iceland (874 AD) and 1690 AD. The second goal was to trace the geographical origin of the Icelandic C1 haplotype outside Iceland. To this end, the complete mtDNA genome was sequenced from eleven Icelandic C1 carriers, allowing it to be placed within the phylogeny of haplogroup C1. Phylogenetic trees were constructed from all 61 complete haplogroup C1 sequences published to date, along with the Icelandic C1 sequence. Interestingly, this analysis revealed that the Icelandic sequence belongs to a new a very distinct sub-clade in C1, named C1e. This leaves us with an even greater mystery than before. The Icelandic C1e haplotype could either be of Native American, European or Asian origin. Further research is necessary to determine which of these regions gave rise to C1e, but at present the strongest evidence points to a Native American origin.

http://skemman.is/bitstream/1946/4339/1/MARitgerdSunna_fixed.pdf