Molecular Phylogenetic Studies on Spinosae Group (Genus Paa) in China (Amphibian, Anura, Ranidae)
|Keywords||Paa mtDNA 12S rRNA 16S rRNA Phytogeny Original center Differential center|
The genus Paa, which was used to be a group of genus Rana, belongs to the Ranidae of the order Anura, in 1975 Mr. Dubois separated the genus Paa from the genus Rana, as an independent genus. But up to now, there are different opinions. The extent of skin spine exists in the males of Paa, which become a natural group. The Paa mainly distributes in Southeast Asia, South Asia and tropics, subtropics of Chinese Qinlin Mountains’ south. There are 29 species of the genus Paa in the world, the animals distribution are east to Chinese coast, west to Afghanistan and Pakistan, south to Viet Nam and Burma, north to the Himalayas Mountains and Qinlin Mountains. There are 21 species of the genus Paa in China, their distribution are east to Fujian and Zhejiang, west to Xizang (Tibet) and Yunnan, south to Guangdong and Guangxi, north to Qinlin Mountains, but no distribution in Taiwan and Hainan. There are 9 species of the genus Paa in Yunnan.Most of the research on Paa in the past focused on morphological taxonomy. There were a few reports involved in their distribution, physiology, embryo, biochemistry, cell heredity (chromosome). Only were mitochondrial sequences of three species in Paa sequenced. The karyotypes of 13 Paa species in China have been described and compared. The results showed that the majority of them have 2n=26, Nf=52, 5+8 formulae, only P. liui and P. yunnanensis 2n=64(T), P. unculuana 2n=40. There are the differences in centromeric position, secondary constrictions, C-bands, and Ag-NORs among the species that possessing 2n=26 karyotype, and same intraspecies population differentiation also. By these results and the data, we could analyze the more relationships and the evolutionary information of the species.By the PCR-Sequence technique, 949bp sequence in 12S rRNA and 16S rRNA gene from samples 45 of 17 species in Paa were sequenced. There were no length variations, indels or gaps in these sequences. Phylogenetic trees were reconstructed by maximum parsimony method using the Limnonects fujianensis as outgroup.Based on these experimental results, with Paa distribution, ancient geological and geographical data, further analysis and study showed that1. The genus Paa, including P. quadranus and P. uncauluanus, is a monophyleticgroup with highly support, phylogenetic trees show that Paa can be divided into three branches. Cladel included P. yei, P. verrucospinosa, P. jiulongensis, P. exilispinosa, P. spinosa, P. boulengeri, P. robertingeri and P. shini. Cladell included P. yunnanensis and P. liui. Cladelll included P. quardrana, P. liebigii, P. maculosa, P. chayuensis, P. blanfordii, P. conaensis and P. unculuana.2. Our analysis didn’t support the view that divided the genus Paa into three subgenera Paa, Quadrana and Unculuana.3. Our results supported that P. verrucospinosa as a species exists in China.4. Our results supported that P. chayuensis and Paa yei as species are efficacious.5. The research didn’t support that P. liui was as an independent species, and should be incorporated into P. yunnanensis.6. Acording to our results, we suggested that the center of origin and differentiation of Paa was probably the boundary of the Henduan Mountains and the Himalayas Mountains, and Paa’s distribution could relate to the bulge of Qinghai-Xizang Plateau and the formation of Henduan Mountains.