Molecular systematics of morphologically similar fishes in the Schizothoracinae in Nanmenxia River, with implication for morphological convergent evolution
With the human activities and changes in water systems due to uplifting of the Qinghai-Tibetan Plateau, gene flow between the schizothoracine fishes distributed in the Nanmenxia River and other upper reaches of the Yellow River has been limited for a long time. As a small and isolated group in a special niche, the investigation of the taxonomic status and evolutionary status of these fishes is important to further understand what has caused the rapid speciation and high levels of biodiversity in the Qinghai-Tibetan Plateau. In this study, the complete sequences of the mitochondrial cyt b gene from 29 individuals of schizothoracine fishes in the Nanmanxia River and 19 individuals representing other relatively closed species were sequenced. Among the aligned sequences of 29 individuals of schizothoracine fishes in the Nanmanxia River, 100 (8.77%) nucleotide sites were variable, and a total of 16 haplotypes was identified. The phylogenetic analyses showed that 5 haplotypes (NMX3, 6,7, 13, 15) from the Nanmanxia River clustered with the relatively closed species Gymnocypris eckloni and Gymnocypris przewahkii, and together formed a monophyletic clade with high boostrap values (99% for the MP tree and 98 % for Bayesian tree). The remaining 11 haplotypes (NMX1, 2, 4, 5, 8, 9, 10, 11, 12, 14, 16) together with Schizopygopsis pylzovi from the upper reaches of the Yellow River formed another monophyletic clade (99% for both the MP tree and Bayesian tree). The sequence divergence between two groups distributed in different clades showed significant (average 7.42%), and together with the results of phylogenetic analyses suggested that schizothoracine fishes in the Nanmanxia River may be a morphologically similar species complex, consisting of two species, Gymnocypris eckloni and Schizopygopsis pylzovi . The natural selective pressure resulted from the changes of the water system and climatic conditions due to uplifts of the plateau, may have promoted adaptive convergence of their morphological characters.
NETL
NSTL
万方数据
维普
