Email updates

Keep up to date with the latest news and content from Investigative Genetics and BioMed Central.

Open Access Highly Accessed Research

Modeling the contrasting Neolithic male lineage expansions in Europe and Africa

Michael J Sikora1, Vincenza Colonna12, Yali Xue1 and Chris Tyler-Smith1*

Author Affiliations

1 The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire CB10 1SA, UK

2 Institute of Genetics and Biophysics, National Research Council (CNR), 80125, Naples, Italy

For all author emails, please log on.

Investigative Genetics 2013, 4:25  doi:10.1186/2041-2223-4-25

Published: 21 November 2013

Abstract

Background

Patterns of genetic variation in a population carry information about the prehistory of the population, and for the human Y chromosome an especially informative phylogenetic tree has previously been constructed from fully-sequenced chromosomes. This revealed contrasting bifurcating and starlike phylogenies for the major lineages associated with the Neolithic expansions in sub-Saharan Africa and Western Europe, respectively.

Results

We used coalescent simulations to investigate the range of demographic models most likely to produce the phylogenetic structures observed in Africa and Europe, assessing the starting and ending genetic effective population sizes, duration of the expansion, and time when expansion ended. The best-fitting models in Africa and Europe are very different. In Africa, the expansion took about 12 thousand years, ending very recently; it started from approximately 40 men and numbers expanded approximately 50-fold. In Europe, the expansion was much more rapid, taking only a few generations and occurring as soon as the major R1b lineage entered Europe; it started from just one to three men, whose numbers expanded more than a thousandfold.

Conclusions

Although highly simplified, the demographic model we have used captures key elements of the differences between the male Neolithic expansions in Africa and Europe, and is consistent with archaeological findings.

Keywords:
Human Y chromosome; Neolithic transition; Population expansion; Demographic modeling; Coalescent simulations; Haplogroup; R1b; E1b1a