Haplogroup K1a1b1a (mtDNA)

Origin

According to National Geographic's Genographic Project, K1a1b1a has an unknown origin. The site states, "Though the origin of this lineage is not clear, it is a founding population among some Jewish Diaspora groups. Among Ashkenazi Jews, it is about 19 percent of maternal lineages. Interestingly, it is also present in some Romani populations". Estimates of the age of K1a1b1a vary depending on the mutation rates used. The age of K1a1b1a has been estimated at 4,800 ± 3600 Years Ago, according to the Genographic Project.

The K1a1b1a subclade is under the U'K haplogroup and descends from K1a1b1, which is thought to be an 11,500-year-old European subclade of mostly non Jewish origins. Haplogroup K falls under the old U8 grouping. Some of the Basque people of Spain and France fall under the U8a subclade within U8. K1a1b1a is a U8b subclade within U8, with several downstream variations.

Ötzi, a mummy who was found September 1991 in the Ötztal Alps, is subclade K1ö for Ötzi. It is interesting to note that Ötzi has mtDNA marker 10978 in common with the Ashkenazi population and others who fall under the K1a1b1a subclade.

A new study and recent updates to the mtDNA tree uses three markers to define K1a1b1a, (114), 10978 and 16234. The marker 12954 along with the previous three markers mentioned, are used to define a new mtDNA subclade called K1a1b1a1. This new group consists of people who are either Ashkenazi or of non Ashkenazi European ancestry.

Distribution

10% of Europeans fall under the K haplogroup. It is hypothesized that the subclade represents one of four major founding maternal lineages ("founding mothers") of Ashkenazi Jews which together account for 45% of all Ashkenazi mtDNA haplotypes. Approximately 19% of Ashkenazi Jews with ancestry from Poland are in mtDNA haplogroup K1a1b1a. However, K1a1b1a has also been found in individuals of no known Jewish ancestry, and the explanation will require further research. The Genographic Project along with other research groups are looking into this phenomenon. The haplogroup is distributed in Europe and the Middle East. Estimates suggest approximately 1,600,000 Jews worldwide would be K1a1b1a.

The recently evolving field of genetic genealogy and DNA sequencing has permitted people of unknown ancestry to make use of DNA testing to establish some evidence for their ancestral origins. Accordingly, based on the research of Behar, some connection has been established between the K1a1b1a subclade and Jewish ancestry, but that remains unclear in light of newer studies as of 2013, as well as the Romani carrying K1a1b1a. The notion of Romani origins for K1a1b1a is very unlikely, given the much greater genetic diversity of K1a1b1a in Jews. This suggests that the presence of K1a1b1a in Romani is more likely the result of introgression into Romani populations.

Version 3 of van Oven's Phylotree defines K1a1b1a by the highly polymorphic 114 in the second hypervariable region, 10978 and 12954 in the coding region, and 16234 in the first hypervariable region. This is supported by a growing number of Genbank samples. However, 12954 is not needed to define K1a1b1a as of 2013 and as mentioned above, is used to define K1a1b1a1.

It may be recognized in hypervariable only samples by essential mutations:

Tree

This phylogenetic tree of haplogroup K subclades is based on the paper by Mannis van Oven and Manfred Kayser Updated comprehensive phylogenetic tree of global human mitochondrial DNA variation and subsequent published research. Newer research has further updated the phylogenetic tree of haplogroup K subclades. However, the K1a1b1a1 subclade has yet to be approved and does not appear in the Build 17 PhyloTree as of February 18th, 2016.