Iceland
Facts
All but one of the Icelandic Y chromosomes belong to Y-haplogroup 1 (41.4%), Y-haplogroup 2 (34.2%), or Y-haplogroup 3 (23.8%).
some Icelandic haplogroup-1 chromosomes are likely to have a Gaelic origin, whereas for most Icelandic haplogroup-2 and -3 chromosomes, a Scandinavian origin is probable.
20%-25% of Icelandic founding males had Gaelic ancestry, with the remainder having Norse ancestry.
The closer relationship with the Scandinavian Y-chromosome pool is supported by the results of analyses of genetic distances and lineage sharing.
Results based on mtDNA data indicate closer matrilineal links with populations of the British Isles. This supports the model, put forward by some historians, that the majority of females in the Icelandic founding population had Gaelic ancestry, whereas the majority of males had Scandinavian ancestry.
Helgason A. et al. traced the matrilineal and patrilineal ancestry of all 131,060 Icelanders born after 1972 back to two cohorts of ancestors, one born between 1848 and 1892 and the other between 1798 and 1742. (12721957)
- This populationwide coalescent analysis of Icelandic genealogies revealed highly positively skewed distributions of descendants to ancestors, with the vast majority of potential ancestors contributing one or no descendants and a minority of ancestors contributing large numbers of descendants. (12721957)
- The expansion and loss of matrilines and patrilines has caused considerable fluctuation in the frequencies of mtDNA and Y-chromosome haplotypes, despite a rapid population expansion in Iceland during the past 300 years.
- Contrary to a widespread assumption, the rate of evolution caused by this lineage-sorting process was markedly faster in matrilines (mtDNA) than in patrilines (Y chromosomes). The primary cause is a 10% shorter matrilineal generation interval. (12721957)
- They observed an intergenerational correlation in offspring number and in the length of generation intervals in the matrilineal and patrilineal genealogies, which was stronger in matrilines and thus contributes to their faster evolutionary rate. These findings may have implications for coalescent date estimates based on mtDNA and Y chromosomes. (12721957)
See also
Y-chromosome
Icelanders
Scandinavians
Gaels
Ireland
Scotland
phylogenetic networks of Y-chromosome variation
haplotypes
diallelic markers
microsatellite markers
clades
References
Helgason A, Hrafnkelsson B, Gulcher JR, Ward R, Stefansson K. A populationwide coalescent analysis of Icelandic matrilineal and patrilineal genealogies: evidence for a faster evolutionary rate of mtDNA lineages than Y chromosomes. Am J Hum Genet. 2003 Jun;72(6):1370-88. PMID: 12721957
Helgason A, Sigureth ardottir S, Nicholson J, Sykes B, Hill EW, Bradley DG, Bosnes V, Gulcher JR, Ward R, Stefansson K. Estimating Scandinavian and Gaelic ancestry in the male settlers of Iceland. Am J Hum Genet. 2000 Sep;67(3):697-717. PMID: 10931763
Helgason A, Hickey E, Goodacre S, Bosnes V, Stefansson K, Ward R, Sykes B. mtDna and the islands of the North Atlantic: estimating the proportions of Norse and Gaelic ancestry. Am J Hum Genet. 2001 Mar;68(3):723-37. PMID: 11179019
Helgason A, Sigureth ardottir S, Gulcher JR, Ward R, Stefansson K. mtDNA and the origin of the Icelanders: deciphering signals of recent population history. Am J Hum Genet. 2000 Mar;66(3):999-1016. PMID: 10712214