Phylogeographic refinement and large scale genotyping of human y chromosome haplogroup e provide new insights into the dispersal of early pastoralists in the African continent

Haplogroup E, defined by mutation M40, is the most common human Y chromosome clade within Africa. To increase the level of resolution of haplogroup E, we disclosed the phylogenetic relationships among 729 mutations found in 33 haplogroup DE Y-chromosomes sequenced at high coverage in previous studies. Additionally, we dissected the E-M35 subclade by genotyping 62 informative markers in 5,222 samples from 118 worldwide populations. The phylogeny of haplogroup E showed novel features compared with the previous topology, including a new basal dichotomy. Within haplogroup E-M35, we resolved all the previously known polytomies and assigned all the E-M35* chromosomes to five new different clades, all belonging to a newly identified subhaplogroup (E-V1515), which accounts for almost half of the E-M35 chromosomes from the Horn of Africa. Moreover, using a Bayesian phylogeographic analysis and a single nucleotide polymorphism-based approach we localized and dated the origin of this new lineage in the northern part of the Horn, about 12ka. Time frames, phylogenetic structuring, and sociogeographic distribution of E-V1515 and its subclades are consistent with a multistep demic spread of pastoralism within north-eastern Africa and its subsequent diffusion to subequatorial areas. In addition, our results increase the discriminative power of the E-M35 haplogroup for use in forensic genetics through the identification of new ancestry-informative markers.
The authors are grateful to all the donors for providing DNA samples and to the people that contributed to the sample collection. In particular, they thank João Lavinha (for the Portuguese samples); Farha El Chennawi, Anne Cambon-Thomsen, M.S. Issad, Eric Crubézy, Abdellatif Baali, Mohammed Cherkaoui, and Mohammed Melhaoui for their help in the collection of the Moroccan, Algerian, and Egyptian Berbers samples; and the National Laboratory for the Genetics of Israeli Populations. This work was supported by the Italian Ministry of Education, Progetti PRIN (grant numbers 2012JA4BTY_004 to F.C. and 2012JA4BTY_003 to A.N.) and by Sapienza University of Rome (grant number C26A13S9AR to F.C.). The sampling of the Berbers was made within the framework of the Inserm "Réseau Nord/Sud" No. 490NS1 (Mozabite Berbers), "The Origin of Man, Language and Languages," EUROCORES Programme and benefited from funding by the Région Midi-Pyrénées (Toulouse, France), the CNRS, and the E.C. Sixth Framework Programme under Contract ERASCT-2003-980409.