Archived Comments for: The history of the North African mitochondrial DNA haplogroup U6 gene flow into the African, Eurasian and American continents

Update of the U6 phylogeny

29 May 2014

Comment posted on behalf of Dr Bernard Secher and his co-authors

The U6 complete sequence HQ651712 of Palestinian origin has the mutations 15626 and 10172. So it is difficult to know if it belongs to the U6a2 or U6a8 subclade. Mainly due to the behavior of the mutation 103 and that mutation 15626 is relatively less frequent (appears in 4 branches of the mtDNA tree of Van Oven and Kayser) than 10172 (appears in 6 branches), we decided in this paper to keep the HQ651712 sequence in the U6a2 subclade. However, recently, a new U6 sequence appeared in the GenBank data base with the id KJ446072. This sequence is very close to the HQ651712 sequence and it is also of Palestinian origin. This new sequence has the mutation 10172, but not the mutation 15626. So we can conclude that both sequences HQ651712 and KJ446072 belong to the U6a8 subclade, and that the mutation 15626 occurred only recently in the HQ651712 sequence. See the revised U6 tree here: http://secher.bernard.free.fr/DNA/AdditionalFile2_new.xls 

The van Oven and Kayser build 16 had already the correct phylogeny.

Accordingly, the mutation 103 is now upstream the two subclades: U6a2 and U6a8. U6a2 is defined by the mutation 15626 and U6a8 is defined by the mutation 10172. The clade U6a2a1 is renamed U6a2a,  the clade U6a2a3 is renamed  U6a8b. The 2 clades U6a2a2 and U6a2c are joined in one clade named: U6a2c defined by the mutation 195. The clade U6a8 is renamed U6a8a. The ages of these new clades estimated from the Soares calculator are the following:

U6a2:16,800 years

U6a2c: 11,300 years

U6a8: 20,800 years

U6a8a: 9,700 years

U6a8b: 4,200 years

Bernard Secher

Competing interests