Abstract:

Many water fowls have a long history of domestication for socio-economic reasons. However, phylogenetic relation in this group remains contradictory. In this study, we infer the divergence time between water fowls with mitochondrial RNAs in order to elucidate speciation events in domestic geese. Firstly, we have extracted DNA from Taihue goose and Landaise goose, which stand respectively for Chinese geese and European geese. Mitochondrial RNAs have been amplified by PCR method. Secondly, we pick up 10 complete mtDNA sequences from GenBank. Then, we reconstruct phylogenetic tree based on Bayesian method and RNA secondary structure. At last, the divergence time is inferred with r8s. The fossils we chose are : (1) a fossil anseriform that sets a minimum age of 11.1 Mya for the common ancestor of swans/brantas and geese. (2) earliest Branta fossil for a minimum age of common ancestry of Anser-Branta at 7.15 Mya. The results: divergence time for common ancestry of Chinese goose and European goose is assigned to 0.61 Mya, and split between Muscovy and Mallard have occurred in the early Miocence, i.e. ,15.5 Mya. Associating divergence time with geological event in Pleistocene, we infer climatic cycles with subsequent glacial and intergalcial periods have had an important impact on speciation of two domestic geese. Results in this study are useful to conservation and utilization of genetic resource in water fowls.