Biochemical Analysis of Relationships of Mediterranean Alectoris Partridges

Abstract

The Mediterranean Alectoris (including A. rufa, A. graeca, A. chukar, and A. barbara) comprise a group of closely related and morphologically uniform partridges with largely allopatric distributions and instances of natural hybridization in parapatric contact zones. Their taxonomic status and evolution are controversial. We have used multilocus protein electrophoresis to estimate the extent of genetic divergence among nominal Alectoris species and within A. chukar, A. graeca and A. rufa. The average Nei's (1978) genetic distance among conspecific populations (D̄ = 0.008; range 0.003-0.021) was 26 times smaller than among species (D̄ = 0.208; range 0.071-0.312). The most genetically similar species were A. rufa and A. graeca (D̄ = 0.081); A. barbara and A. chukar were the most divergent (D̄ = 0.303). The Fst values among species (Fst=0.75) were more than eight times larger than among conspecific populations (Fst=0.09). The gap in D and Fst values for intraspecific and interspecific comparisons indicates a prolonged interruption of gene flow among species and independent evolution of their gene pools. Dendrograms summarizing genetic distance matrices and cladistic analyses of discrete character states suggested that A. rufa and A. graeca are sister species of recent origin, followed by the most distantly related and ancient A. chukar and A. barbara. Because protein electrophoresis results are concordant with biogeographical and paleontological information, we construct a hypothesis for the evolution of the Mediterranean Alectoris.