Thomas Jefferson's Y chromosome belongs to a rare European lineage

Abstract

We have characterized the Y chromosome carried by President Thomas Jefferson, the general rarity of which supported the idea that he, or a patrilineal relative, fathered the last son of his slave Sally Hemings. It belongs to haplogroup K2, a lineage representing only approximately 1% of chromosomes worldwide, and most common in East Africa and the Middle East. Phylogenetic network analysis of its Y-STR (short tandem repeat) haplotype shows that it is most closely related to an Egyptian K2 haplotype, but the presence of scattered and diverse European haplotypes within the network is nonetheless consistent with Jefferson's patrilineage belonging to an ancient and rare indigenous European type. This is supported by the observation that two of 85 unrelated British men sharing the surname Jefferson also share the President's Y-STR haplotype within haplogroup K2. Our findings represent a cautionary tale in showing the difficulty of assigning individual ancestry based on a Y-chromosome haplotype, particularly for rare lineages where population data are scarce.

Paternal Genetic History of the Basque Population of Spain

“…Morelli et al (2010) used an evolutionary effective mutation rate (Zhivotovsky 2001;Zhivotovsky et al 2004), whereas Balaresque et al (2010) used an STR-specific germline mutation rate, which can bias estimates downward under conditions of constant population size. Haplogroup I2a2 has previously been reported among Basques (6%), the populations of Castile (19%), Bernais (7.7%), and Normandy (2.4%), as well as the Irish (2.6%), with a high of 40.9% in Sardinia (Flores et al 2004; Rootsi et King et al (2007) al. 2004).…”

“…It is present at low frequencies in other Western European groups, including Britain (0.5%), Western France (0.5%), Sardinia (1.3%), and Greece (1.3%). Haplogroup T is also found in African populations in Egypt (7.2%), Ethiopia (4.8%), and Somalia (10.5%) and in Middle Eastern groups in Iraq (7.2%), Turkey (2.5%), and Oman (8.3%) (King et al 2007). This haplogroup has been dated to 20,700 yrs ago, and network analysis suggests that haplogroup T is "an ancient and diverse indigenous European lineage, rather than recent immigrants from the Middle East or Africa" (King et al 2007:585).…”

DNA and bone structure preservation in medieval human skeletons

“…The survival of ancient DNA is of particular interest since DNA technology has been increasingly used in archaeological forensics, for example, for the identification of diseases [1,2], identification of migration patterns [3,4] and patrilineage determination [5].…”

Analysis of SNP (single nucleotide polymorphism) multiplex markers related to sudden cardiac death in Brazilian families

“…Both the father and son were presented with the polymorphic base "T" for this SNP. Following analyses of the Y chromosome, these individuals were classified into the rare T haplogroup, which is found in low frequencies in Europe and parts of the Middle East, North and West Africa (King et al, 2007).…”