The phylogenetic relationships of European and African Barbus and their West Asian relatives in Cyprininae remain largely unresolved.Consequently,little is known about the drivers of their evolution,including the possible association of uplifting of the Qinghai-Tibetan Plateau(QTP)with the early divergence of the subfamily.We use complete sequence data of the mitochondrial DNA gene encoding the protein cytochrome b(Cytb)to hypothesize the phylogeny of 85 species belonging to 47 genera in the Cyprininae plus 6 species from the Leuciscinae.We employ 6 other species from Cypriniformes as outgroup taxa and estimate divergence times.Our results indicate that European Barbus sensu stricto lineage including Aulopyge shares a common ancestor with specialized and highly specialized schizothoracins and the genera Cyprinion and Scaphiodonichtys.The common ancestor appears to have originated in the Qinghai-Tibetan Plateau(QTP)region about 19.4–17.8 Ma.Barbus sensu stricto lineage appears to have originated about 16.6–15.5 Ma.Small to medium sized African Barbus sensu lato appear to have had an Oriental origin about 19.1–15.3 Ma and are closely related to Asian Puntius.West Asian Carasobarbus lineage including large African Barbus sensu lato might have originated about 9.94 Ma,also in Oriental Realm and has a close relationship to Asian Neolissochilus and Tor.The large-sized Barbus sensu lato appear to have diverged from Carasobarbus about 7.7 Ma.Finally,the Cyprininae appear to have radiated rapidly into nine lineages and many sublineages from about 27.8 to 17.8 Ma,close to the time of the second-stage tectonic movements of the QTP.Our analyses provide evidence that the uplifting of the QTP drove early diversification of the Cyprininae.Our extensive sampling of species involving all of the important areas results in clear evolutionary scenario for the Cyprininae.
WANG JingWU XiaoYunCHEN ZiMingYUE ZhaoPingMA WeiCHEN ShanYuanXIAO HengMURPHY Robert WZHANG YaPingZAN RuiGuangLUO Jing
The occurrence of polyploidy,or whole genome duplication,can result in instantaneous speciation.Because new polyploids are immediately reproductively isolated from their non-polyploid congeners,polyploidization has played an important role in the diversification of flowering plants and some vertebrates.Newly formed polyploids must respond to this instantaneous genomic change,which resembles "genome shock" syndrome to survive and reproduce successfully.Epigenetic changes,which do not cause changes to the sequence of DNA,can significantly contribute to the survival of and ultimately to the evolutionary success of new polyploids.Epigenetic regulation,both transcriptional and post-transcriptional,entails changes in DNA methylation,gene status and/or nucleolus dominance.These changes provide effective and flexible ways for a new polyploid to respond quickly to the enormous change in genetic material,to survive and potentially reproduce.We examine and assess certain epigenetic phenomena and possible pathways that may facilitate the evolutionary success of polyploid organisms.
LI ZhiHuiLU XiangGAO YunLIU ShaoJunTAO MinXIAO HengQIAO YunQianZHANG YaPingLUO Jing
