New sublineages in Y-DNA haplogroups A3 and B2a

Improving the knowledge of African genetics.

Rosaria Scozzari et al., Molecular Dissection of the Basal Clades in the Human Y Chromosome Phylogenetic Tree. PLoS ONE 2013. Open access → LINK [doi:10.1371/journal.pone.0049170]

Abstract

One hundred and forty-six previously detected mutations were more precisely positioned in the human Y chromosome phylogeny by the analysis of 51 representative Y chromosome haplogroups and the use of 59 mutations from literature. Twenty-two new mutations were also described and incorporated in the revised phylogeny. This analysis made it possible to identify new haplogroups and to resolve a deep trifurcation within haplogroup B2. Our data provide a highly resolved branching in the African-specific portion of the Y tree and support the hypothesis of an origin in the north-western quadrant of the African continent for the human MSY diversity.

Figure 1. Revised topology of the deepest portion of the human MSY tree.

The names of the mutations genotyped are indicated on the branches (green, mutations from the paper by Karafet et al. [14]; black, mutations from the paper by Cruciani et al. [16]; red, previously undescribed mutations, see text). For the sake of clarity, the internal structure of haplogroups B-M108.1 (2 branches) and B-50f2(P) (8 branches) is not shown (black triangles). The phylogenetic position of mutations mapping within haplogroup CT is shown in Figure S1. Dashed lines indicate putative branchings (no positive control available). The microsatellite intermediate allele DYS449.2, that was found to delineate new phylogenetic structure in human Y chromosome haplogroup tree [42], was not observed in 19 Y*(xBT) and 4 B chromosomes analyzed.

Notice that the nomenclature per ISOGG is right now as follows:

• A1b-V148 is now known as A0
• A1a-V4 retains the name A1a
• A2-V50 is A1b1a
• A3-M32 is A1b1b
• A3a-M28 is A1b1b1
• A3b-M144 is A1b1b2

See ISOGG for more details.