title: Gene flow from North Africa contributes to differential human genetic diversity in southern Europe.
abstract: Human genetic diversity in southern Europe is higher than in other regions of the continent. This difference has been attributed to postglacial expansions, the demic diffusion of agriculture from the Near East, and gene flow from Africa. Using SNP data from 2,099 individuals in 43 populations, we show that estimates of recent shared ancestry between Europe and Africa are substantially increased when gene flow from North Africans, rather than Sub-Saharan Africans, is considered. The gradient of North African ancestry accounts for previous observations of low levels of sharing with Sub-Saharan Africa and is independent of recent gene flow from the Near East. The source of genetic diversity in southern Europe has important biomedical implications; we find that most disease risk alleles from genome-wide association studies follow expected patterns of divergence between Europe and North Africa, with the principal exception of multiple sclerosis.
authors.affiliation: Institut de Biologia Evolutiva, Consejo Superior de Investigaciones Científicas-Universitat Pompeu Fabra, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, 08003 Barcelona, Spain.
authors.forename: Laura R
authors.initials: LR
authors.lastname: Botigué
authors.forename: Brenna M
authors.initials: BM
authors.lastname: Henn
authors.forename: Simon
authors.initials: S
authors.lastname: Gravel
authors.forename: Brian K
authors.initials: BK
authors.lastname: Maples
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Gignoux
authors.forename: Erik
authors.initials: E
authors.lastname: Corona
authors.forename: Gil
authors.initials: G
authors.lastname: Atzmon
authors.forename: Edward
authors.initials: E
authors.lastname: Burns
authors.forename: Harry
authors.initials: H
authors.lastname: Ostrer
authors.forename: Carlos
authors.initials: C
authors.lastname: Flores
authors.forename: Jaume
authors.initials: J
authors.lastname: Bertranpetit
authors.forename: David
authors.initials: D
authors.lastname: Comas
authors.forename: Carlos D
authors.initials: CD
authors.lastname: Bustamante
mesh_terms: D000352:Africa, Northern; D003710:Demography; D005060:Europe; D051456:Gene Flow / Q000235:genetics*; D014644:Genetic Variation; D005828:Genetics, Population; D006239:Haplotypes / Q000235:genetics; D049690:History, Ancient; D006801:Humans; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D044465:White People / Q000235:genetics* / Q000266:history*
keywords: IBD segments; Iberia; Maghreb; admixture; population genetics