The data presented here are consistent with a scenario in which proto-Berber-speaking ovicaprid pastoralists introduced the –13910T allele, and thereby lactose tolerance, into North Africa. This scenario implies a genetic input from migrating pastoralists from the Middle East and suggests that contemporary Berber populations share a Middle Eastern dairying origin with other Eurasian populations.
See also A Predominantly Neolithic Origin for Y-Chromosomal DNA Variation in North Africa and Lactase Persistence in Africans and Back-Migration from Eurasia.
Human Genetics (Online Early)
Genetic evidence in support of a shared Eurasian-North African dairying origin
Abstract The process by which pastoralism and agriculture spread from the Fertile Crescent over the past 10,000 years has been the subject of intense investigation by geneticists, linguists and archaeologists. However, no consensus has been reached as to whether this Neolithic transition is best characterized by a demic diffusion (with a significant genetic input from migrating farmers) or a cultural diffusion (without substantial migration of farmers). Milk consumption and thus lactose tolerance are assumed to have spread with pastoralism and we propose that by looking at the relevant mutations in and around the lactase gene in human populations, we can gain insight into the origin(s) and spread of dairying. We genotyped the putatively causal allele for lactose tolerance (–13910T) and constructed haplotypes from several polymorphisms in and around the lactase gene (LCT) in three North African Berber populations and compared our results with previously published data. We found that the frequency of the –13910T allele predicts the frequency of lactose tolerance in several Eurasian and North African Berber populations but not in most sub-Saharan African populations. Our analyses suggest that contemporary Berber populations possess the genetic signature of a past migration of pastoralists from the Middle East and that they share a dairying origin with Europeans and Asians, but not with sub-Saharan Africans.