MITOCHONDRIAL-DNA SEQUENCE VARIATION AMONG THE SUBSPECIES OF SARUS CRANE (GRUS ANTIGONE)

We examined DNA sequence variation in an 1,831 base-pair segment of th e mitochondrial DNA genome from representatives of the three subspecie s of Sarus Crane (Grus antigone). The sequences include the entire cyt ochrome-b, tRNA(Thr), tRNA(Pro), and ND6 genes, as well as three short intergenic spacer regions. Nine distinct haplotypes were identified i n a sample of nine individuals, three each from the Indian (G. a. anti gone), Burmese (G. a. sharpei), and Australian (G. a. gillae) subspeci es. Phylogenetic analysis revealed that although Sarus Crane haplotype s form a monophyletic assemblage relative to Brolga (G. rubicunda) and White-naped Crane (G. vipio) outgroups, they cannot be resolved onto a dichotomously branching tree. A minimum-length network for the Sarus Crane haplotypes reveals at least one instance of direct ancestry and one hard polytomy, but shows no phylogeographic partitioning of haplo types among subspecies. Net sequence divergence among subspecies is no t significantly different from zero. Estimated sequence divergence tim es, neutral coalescent limes, and data on the Quaternary geology of Au stralasia suggest that Sarus Cranes colonized Australia during the lat e Pleistocene.