DNA barcoding and molecular phylogeny in Ranidae

The family Ranidae has the widest distribution compared with other frog family. The phylogeny of the Ranidae is still a matter of dispute. In the present study, we analyzed the COI barcodes of 29 species from six genera belonging to the family Ranidae. Twenty-seven species (93.10% of all the species) were correctly identified by their DNA barcodes. Pelophylax lessonae and Pelophylax ridibundus shared the same one barcode sequence. Kimura two-parameter distances were calculated between barcodes. Pair-wise comparisons among-species were distributed from 0.16% (between Pelophylax lessonae and Pelophylax esculenta) to 29.13% (between Rana warszewitschii and Rana dybowskii). The average genetic distance between species was 28 times higher than the average genetic distance within species. The neighbor-joining method was used to construct a phylogenetic tree, which grouped all the genera into two divergent clades. The results indicated that some currently recognized genera of Ranidae may not be monophyletic. COI gene data supported the hypothesis of polyphyly for Rana, Amolops, Babina, and Hylarana. DNA barcoding is an effective molecular tool for Ranidae species identification and phylogenetic inference.