Human Y chromosome haplogroup R-V88: a paternal genetic record of early mid Holocene trans-Saharan connections and the spread of Chadic languages

Fulvio Cruciani¹, Beniamino Trombetta¹, Daniele Sellitto², Andrea Massaia¹, Giovanni Destro-Bisol³, Elizabeth Watson⁴, Eliane Beraud Colomb⁵, Jean-Michel Dugoujon⁶, Pedro Moral⁷ and Rosaria Scozzari¹

1. ¹Dipartimento di Genetica e Biologia Molecolare, Sapienza Università di Roma, Rome, Italy
2. ²Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, Rome, Italy
3. ³Dipartimento di Biologia Animale e dell’Uomo and Istituto Italiano di Antropologia, Sapienza Università di Roma, Rome, Italy
4. ⁴The Swedish Museum of Natural History, Stockholm, Sweden
5. ⁵Laboratoire d’Immunologie, Hôpital the Sainte-Marguerite, Marseille, France
6. ⁶Laboratoire d’Anthropobiologie, FRE 2960, Centre National de la Recherche Scientifique (CNRS) Université Paul Sabatier, Toulouse, France
7. ⁷Departament of Biologia Animal, Universitat de Barcelona, Barcelona, Spain

Correspondence: Professor R Scozzari, Dipartimento di Genetica e Biologia Molecolare, Sapienza Università di Roma, P.le Aldo Moro 5, Rome 00185, Italy. Tel: +39 06 49912826; Fax: +39 06 4456866; E-mail: rosaria.scozzari@uniroma1.it

Received 27 August 2009; Revised 24 November 2009; Accepted 26 November 2009; Published online 6 January 2010.

Although human Y chromosomes belonging to haplogroup R1b are quite rare in Africa, being found mainly in Asia and Europe, a group of chromosomes within the paragroup R-P25^* are found concentrated in the central-western part of the African continent, where they can be detected at frequencies as high as 95%. Phylogenetic evidence and coalescence time estimates suggest that R-P25^* chromosomes (or their phylogenetic ancestor) may have been carried to Africa by an Asia-to-Africa back migration in prehistoric times. Here, we describe six new mutations that define the relationships among the African R-P25^* Y chromosomes and between these African chromosomes and earlier reported R-P25 Eurasian sub-lineages. The incorporation of these new mutations into a phylogeny of the R1b haplogroup led to the identification of a new clade (R1b1a or R-V88) encompassing all the African R-P25^* and about half of the few European/west Asian R-P25^* chromosomes. A worldwide phylogeographic analysis of the R1b haplogroup provided strong support to the Asia-to-Africa back-migration hypothesis. The analysis of the distribution of the R-V88 haplogroup in >1800 males from 69 African populations revealed a striking genetic contiguity between the Chadic-speaking peoples from the central Sahel and several other Afroasiatic-speaking groups from North Africa. The R-V88 coalescence time was estimated at 9200–5600 kya, in the early mid Holocene. We suggest that R-V88 is a paternal genetic record of the proposed mid-Holocene migration of proto-Chadic Afroasiatic speakers through the Central Sahara into the Lake Chad Basin, and geomorphological evidence is consistent with this view.

Keywords: 

Y chrom

Keywords: 

Y chromosome haplogroups; human migrations; Holocene; Africa; Chadic-speaking populations

http://www.nature.com/ejhg/journal/v18/n7/abs/ejhg2009231a.html