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African buffalo maintain high genetic diversity in the major histocompatibility complex in spite of historically known population bottlenecks
Author(s) -
WENINK P. W.,
GROEN A. F.,
ROELKEPARKER M. E.,
PRINS H. H. T.
Publication year - 1998
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1046/j.1365-294x.1998.00463.x
Subject(s) - biology , loss of heterozygosity , locus (genetics) , balancing selection , allele , genetics , major histocompatibility complex , inbreeding , population , gene pool , population bottleneck , genetic diversity , evolutionary biology , gene , demography , microsatellite , sociology
Historical population collapses caused by rinderpest epidemics are hypothesized to have resulted in notable genetic losses in populations of the African buffalo. Polymorphism in the major histocompatibity complex (MHC) DRB3 gene was probed by means of restriction analysis of the sequence encoding the peptide‐binding region. Nucleotide substitution patterns agreed with a positive selection acting on this fitness‐relevant locus. Buffalo populations from four National Parks, situated in eastern and southern Africa, each revealed a surprisingly high allelic diversity. Current high levels of heterozygosity may be reconciled with historical bottlenecks by assuming that local extinctions were followed by fast recolonization, in accordance with the high dispersive capabilities of buffalo. The specific amplification of DRB3 alleles also enabled the assignment of individual genotypes. For each population sample a deficiency in the expected number of heterozygous animals was found. As overdominant selection on the MHC is predicted to yield an excess of heterozygous individuals, this may not be a locus‐specific effect. Several other explanations are discussed, of which increased homozygosity caused by nonrandom mating of buffalo in populations seems the most probable.