Phylogeography and population structure of the saker falcon (Falco cherrug) and the influence of hybridization: mitochondrial and microsatellite data

Abstract

Microsatellite as well as sequence analysis of the mitochondrial control region were applied to infer phylogeography and population genetic structure of the saker falcon (Falco cherrug). Furthermore, we compared the patterns of mitochondrial haplotypes with the variation of microsatellite alleles among the species of the hierofalcon complex (F. cherrug, Falco rusticolus, Falco biarmicus, Falco jugger) to test hypotheses on population history. Historical samples from museum specimens of F. cherrug were analysed together with samples from contemporary populations to investigate possible influences of hybrid falcons escaped from falconry on the genetic composition. In the mitochondrial DNA analysis, none of the four species represents a monophyletic group. Moreover, there are no clearly defined groups of haplotypes corresponding to taxonomic entities. In the microsatellite analysis most of the variation is shared between species and no clear differentiation by private alleles is found. Yet, with a Bayesian clustering method based on allele frequencies, a differentiation of F. cherrug, F. rusticolus and two geographic groups of F. biarmicus was detected. Results from both nuclear and mitochondrial markers are compatible with the previously postulated 'Out of Africa' hypothesis assuming an African origin of the hierofalcons. From an ancestral African population, F. cherrug, F. rusticolus and F. jugger split off in separate waves of immigration into Eurasia and South Asia. A combination of evolutionary processes, including incomplete lineage sorting as well as hybridization, may be responsible for the currently observed genetic patterns in hierofalcons.