title: The genetic structure and history of Africans and African Americans.
abstract: Africa is the source of all modern humans, but characterization of genetic variation and of relationships among populations across the continent has been enigmatic. We studied 121 African populations, four African American populations, and 60 non-African populations for patterns of variation at 1327 nuclear microsatellite and insertion/deletion markers. We identified 14 ancestral population clusters in Africa that correlate with self-described ethnicity and shared cultural and/or linguistic properties. We observed high levels of mixed ancestry in most populations, reflecting historical migration events across the continent. Our data also provide evidence for shared ancestry among geographically diverse hunter-gatherer populations (Khoesan speakers and Pygmies). The ancestry of African Americans is predominantly from Niger-Kordofanian (approximately 71%), European (approximately 13%), and other African (approximately 8%) populations, although admixture levels varied considerably among individuals. This study helps tease apart the complex evolutionary history of Africans and African Americans, aiding both anthropological and genetic epidemiologic studies.
authors.affiliation: Department of Biology, University of Maryland, College Park, MD 20742, USA. tishkoff@mail.med.upenn.edu
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Tishkoff
authors.forename: Floyd A
authors.initials: FA
authors.lastname: Reed
authors.forename: Françoise R
authors.initials: FR
authors.lastname: Friedlaender
authors.forename: Christopher
authors.initials: C
authors.lastname: Ehret
authors.forename: Alessia
authors.initials: A
authors.lastname: Ranciaro
authors.forename: Alain
authors.initials: A
authors.lastname: Froment
authors.forename: Jibril B
authors.initials: JB
authors.lastname: Hirbo
authors.forename: Agnes A
authors.initials: AA
authors.lastname: Awomoyi
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Bodo
authors.forename: Ogobara
authors.initials: O
authors.lastname: Doumbo
authors.forename: Muntaser
authors.initials: M
authors.lastname: Ibrahim
authors.forename: Abdalla T
authors.initials: AT
authors.lastname: Juma
authors.forename: Maritha J
authors.initials: MJ
authors.lastname: Kotze
authors.forename: Godfrey
authors.initials: G
authors.lastname: Lema
authors.forename: Jason H
authors.initials: JH
authors.lastname: Moore
authors.forename: Holly
authors.initials: H
authors.lastname: Mortensen
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Nyambo
authors.forename: Sabah A
authors.initials: SA
authors.lastname: Omar
authors.forename: Kweli
authors.initials: K
authors.lastname: Powell
authors.forename: Gideon S
authors.initials: GS
authors.lastname: Pretorius
authors.forename: Michael W
authors.initials: MW
authors.lastname: Smith
authors.forename: Mahamadou A
authors.initials: MA
authors.lastname: Thera
authors.forename: Charles
authors.initials: C
authors.lastname: Wambebe
authors.forename: James L
authors.initials: JL
authors.lastname: Weber
authors.forename: Scott M
authors.initials: SM
authors.lastname: Williams
mesh_terms: D000349:Africa; D001741:Black or African American / Q000208:ethnology / Q000235:genetics*; D001499:Bayes Theorem; D044383:Black People / Q000208:ethnology / Q000235:genetics*; D016000:Cluster Analysis; D004641:Emigration and Immigration; D005006:Ethnicity / Q000235:genetics; D051456:Gene Flow; D014644:Genetic Variation; D005838:Genotype; D005843:Geography; D006801:Humans; D054643:INDEL Mutation; D007802:Language; D018895:Microsatellite Repeats; D010802:Phylogeny; D020641:Polymorphism, Single Nucleotide; D025341:Principal Component Analysis; D044469:Racial Groups / Q000235:genetics