title: Brief communication: mtDNA variation in North Cameroon: lack of Asian lineages and implications for back migration from Asia to sub-Saharan Africa.
abstract: The hypervariable region-1 and four nucleotide positions (10400, 10873, 12308, and 12705) of the coding region of mitochondrial DNA (mtDNA) were analyzed in 441 individuals belonging to eight populations (Daba, Fali, Fulbe, Mandara, Uldeme, Podokwo, Tali, and Tupuri) from North Cameroon and four populations (Bakaka, Bassa, Bamileke, and Ewondo) from South Cameroon. All mtDNAs were assigned to five haplogroups: three sub-Saharan (L1, L2, and L3), one northern African (U6), and one European (U5). Our results contrast with the observed high frequencies of a Y-chromosome haplogroup of probable Asian origin (R1*-M173) in North Cameroon. As a first step toward a better understanding of the evident discrepancy between mtDNA and Y-chromosome data, we propose two contrasting scenarios. The first one, here termed "migration and asymmetric admixture," implies a back migration from Asia to North Cameroon of a population group carrying the haplotype R1*-M173 at high frequency, and an admixture process restricted to migrant males. The second scenario, on the other hand, temed "divergent drift," implies that modern populations of North Cameroon originated from a small population group which migrated from Asia to Africa and in which, through genetic drift, Y-chromosome haplotype R1*-M173 became predominant, whereas the Asian mtDNA haplogroups were lost.
authors.affiliation: Department of Animal and Human Biology, University La Sapienza, 00185 Rome, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Coia
authors.forename: Giovanni
authors.initials: G
authors.lastname: Destro-Bisol
authors.forename: Fabio
authors.initials: F
authors.lastname: Verginelli
authors.forename: Cinzia
authors.initials: C
authors.lastname: Battaggia
authors.forename: Ilaria
authors.initials: I
authors.lastname: Boschi
authors.forename: Fulvio
authors.initials: F
authors.lastname: Cruciani
authors.forename: Gabriella
authors.initials: G
authors.lastname: Spedini
authors.forename: David
authors.initials: D
authors.lastname: Comas
authors.forename: Francesc
authors.initials: F
authors.lastname: Calafell
mesh_terms: D017954:Africa South of the Sahara; D001208:Asia; D044383:Black People / Q000235:genetics; D002163:Cameroon; D004272:DNA, Mitochondrial / Q000235:genetics*; D004641:Emigration and Immigration; D014644:Genetic Variation; D006801:Humans
chemical_list: D004272:DNA, Mitochondrial