The genus Sinocyclocheilus is distributed in Yun-Gui Plateau and its surrounding region only, within more than 10 cave species showing different degrees of degeneration of eyes and pigmentation with wonderful adaptati...The genus Sinocyclocheilus is distributed in Yun-Gui Plateau and its surrounding region only, within more than 10 cave species showing different degrees of degeneration of eyes and pigmentation with wonderful adaptations. To present, published morphological and molecular phylogenetic hypotheses of Sinocyclocheilus from prior works are very different and the relationships within the genus are still far from clear. We obtained the sequences of cytochrome b (cyt b) and NADH dehydrogenase subunit 4 (ND4) of 34 species within Sinocyclocheilus, which represent the most dense taxon sampling to date. We performed Bayesian mixed models analyses with this data set. Under this phylogenetic framework, we estimated the divergence times of recovered clades using different methods under relaxed mo-lecular clock. Our phyloegentic results supported the monophyly of Sinocyclocheilus and showed that this genus could be subdivided into 6 major clades. In addition, an earlier finding demonstrating the polyphyletic of cave species and the most basal position of S. jii was corroborated. Relaxed diver-gence-time estimation suggested that Sinocyclocheilus originated at the late Miocene, about 11 million years ago (Ma), which is older than what have been assumed.展开更多
A PCR survey for Sox genes in a young tetraploid fish Tor douronensis (Teleostei:Cyprinidae) was per-formed to access the evolutionary fates of important functional genes after genome duplication caused by polyploidiz...A PCR survey for Sox genes in a young tetraploid fish Tor douronensis (Teleostei:Cyprinidae) was per-formed to access the evolutionary fates of important functional genes after genome duplication caused by polyploidization event. Totally 13 Sox genes were obtained in Tor douronensis,which represent SoxB,SoxC and SoxE groups. Phylogenetic analysis of Sox genes in Tor douronensis provided evidence for fish-specific genome duplication,and suggested that Sox19 might be a teleost specific Sox gene member. Sequence analysis revealed most of the nucleotide substitutions between duplicated copies of Sox genes caused by tetraploidization event or their orthologues in other species are silent substitutions. It would appear that the sequences are under purifying selective pressure,strongly suggesting that they repre-sent functional genes and supporting selection against all null allele at either of two duplicated loci of Sox4a,Sox9a and Sox9b. Surprising variations of the intron length and similarities of two duplicated copies of Sox9a and Sox9b,suggest that Tor douronensis might be an allotetraploidy.展开更多
基金the National Basic Research Program of China (Grant No. 2007CB411600) the National Natural Science Foundation of China (Grant No. 30530120)
文摘The genus Sinocyclocheilus is distributed in Yun-Gui Plateau and its surrounding region only, within more than 10 cave species showing different degrees of degeneration of eyes and pigmentation with wonderful adaptations. To present, published morphological and molecular phylogenetic hypotheses of Sinocyclocheilus from prior works are very different and the relationships within the genus are still far from clear. We obtained the sequences of cytochrome b (cyt b) and NADH dehydrogenase subunit 4 (ND4) of 34 species within Sinocyclocheilus, which represent the most dense taxon sampling to date. We performed Bayesian mixed models analyses with this data set. Under this phylogenetic framework, we estimated the divergence times of recovered clades using different methods under relaxed mo-lecular clock. Our phyloegentic results supported the monophyly of Sinocyclocheilus and showed that this genus could be subdivided into 6 major clades. In addition, an earlier finding demonstrating the polyphyletic of cave species and the most basal position of S. jii was corroborated. Relaxed diver-gence-time estimation suggested that Sinocyclocheilus originated at the late Miocene, about 11 million years ago (Ma), which is older than what have been assumed.
基金the National Natural Science Foundation of China (Grant No. 30530120)
文摘A PCR survey for Sox genes in a young tetraploid fish Tor douronensis (Teleostei:Cyprinidae) was per-formed to access the evolutionary fates of important functional genes after genome duplication caused by polyploidization event. Totally 13 Sox genes were obtained in Tor douronensis,which represent SoxB,SoxC and SoxE groups. Phylogenetic analysis of Sox genes in Tor douronensis provided evidence for fish-specific genome duplication,and suggested that Sox19 might be a teleost specific Sox gene member. Sequence analysis revealed most of the nucleotide substitutions between duplicated copies of Sox genes caused by tetraploidization event or their orthologues in other species are silent substitutions. It would appear that the sequences are under purifying selective pressure,strongly suggesting that they repre-sent functional genes and supporting selection against all null allele at either of two duplicated loci of Sox4a,Sox9a and Sox9b. Surprising variations of the intron length and similarities of two duplicated copies of Sox9a and Sox9b,suggest that Tor douronensis might be an allotetraploidy.
