Three fundamental contributions of molecular genetics to avian ecology and evolution

Studies in molecular genetics are having revisionary impact in at least three broad areas of avian ecology and evolution: mating systems, geographic population structure and gene flow, and phylogenetic relationships among species and higher taxa. With regard to mating systems, genetic analyses of maternity and paternity have revealed unexpectedly high frequencies of extra-pair fertilization and intraspecific brood parasitism in numerous avian species (including those thought to be socially monogamous), and these discoveries are prompting a fundamental reshaping of mating system theory for birds. With regard to genetic structure, molecular markers have uncovered a great variety of depths and patterns in the phylogeographic histories of conspecific populations, and these findings provide novel perspectives on historical gene flow regimes and species concepts. With regard to evolutionary relationships among higher avian taxa, molecular findings have suggested several phylogenetic realignments, thus prompting renewed interest in the cross-comparative aspects of molecular and morphological evolution as well as of alternative procedures for molecular analysis.