Phylogenetic Relationships of Chinese Brown Frogs Inferred from Mitochondrial DNA Sequence of 12 S Ribosome RNA Gene

Aligned 393 base pairs of the mitochondrial 12S rRNA gene from 6 species of Chinese brown frogs,and Fejervarya limnocharis,Pelophylax nigromaculata and P.plancyi selected as outgroup were sequenced.Pairwise comparisons showed that the site variability between ingroup and outgroup members ranged from 7.3% to 23.1%.The variability among ingroup members ranged from 0.0% to 9.2%.Phylogenetic analyses based on these DNA sequence data by the neighbor-joining and maximum parsimony methods showed:1)These six species of Chinese brown frogs grouped together and formed a monophyletic clade (BPs value >90%).2)The six species of ingroup were divided two sister groups,I.e.Rana chensinensis,R.amurensis,and R.huanrenensis clustered together (BPs value >94%),and R.omeimontis,R.chaochiaoensis and R.zhenhaiensis formed another cluster (BPs value >50%).3)R.chaochiaoensis was more closed to R.zhenhaiensis than R.omeimontis.4)The Yuzhong population of R.chensinensis related to R.huanrenensis while the Mudanjiang population of R.chensinensis was close to R.amurensis.This indicates that the differentiation between the two populations of R.chensinensis is likely to be at species level.So R.kukunoris including the Yuzhong population of R.chensinensis and R.dybowskii including the Mudanjiang population of R.chensinensis may be revived as two valid species.