Drift Rather than Selection Dominates MHC Class II Allelic Diversity Patterns at the Biogeographical Range Scale in Natterjack Toads Bufo calamita

摘要: Study of major histocompatibility complex (MHC) loci has gained great popularity in recent years, partly due to their function protecting vertebrates from infections. This is particular interest amphibians on account threats many species face emergent diseases such as chytridiomycosis. In this study we compare levels diversity an expressed MHC class II locus with neutral genetic at microsatellite natterjack toad (Bufo (Epidalea) calamita) populations across the whole species’ biogeographical range. Variation both classes was high glacial refugium areas (REF) and much lower postglacial expansion (PGE), especially range edge populations. Although there clear evidence that influenced by positive selection past, congruence markers suggested historical demographic events were main force shaping variation PGE area. Both adaptive declined distance refugia. Nevertheless, also some indications differential isolation allele abundance patterns weak effects have been superimposed drift effect zone.