Atraphaxis has approximately 25 species and a distribution center in Central Asia. It has been previously used to hypothesize an origin from montane forest. We sampled 18 species covering three sections within the gen...Atraphaxis has approximately 25 species and a distribution center in Central Asia. It has been previously used to hypothesize an origin from montane forest. We sampled 18 species covering three sections within the genus and sequenced five cpDNA spacers, atpB -rbcL, psbK -psbI, psbA -trnH, rbcL, and trnL -trnF. BEAST was used to reconstruct phylogenetic relationship and time divergences, and S-DIVA and Lagrange were used, based on distribution area and ecotype data, for reconstruction of ancestral areas and events. Our results appear compatible with designation of three taxonomic sections within the genus. The generic stem and crown ages were Eocene, approximately 47 Ma, and Oligocene 27 Ma,respectively. The origin of Atraphaxis is confirmed as montane,with an ancestral area consisting of the Junggar Basin and uplands of the Pamir-Tianshan-Alatau-Altai mountain chains,and ancestral ecotype of montane forest. Two remarkable paleogeographic events, shrinkage of the inland Paratethys Sea at the boundary of the late Oligocene and early Miocene, and the time intervals of cooling and drying of global climate from24（22） Ma onward likely facilitated early diversification of Atraphaxis, while rapid uplift of the Tianshan Mountains during the late Miocene may have promoted later diversification.展开更多
Traditionally, Atraphaxis, Calligonum, Pteropyrum and Parapteropyrum are included in the tribe Atraphxideae. Recently, sequence data has revealed that this tribe is not monophyletic. The structure of the tribe was exa...Traditionally, Atraphaxis, Calligonum, Pteropyrum and Parapteropyrum are included in the tribe Atraphxideae. Recently, sequence data has revealed that this tribe is not monophyletic. The structure of the tribe was examined by adding more taxa and sequences to clarify the congruence between morphology and molecular phylogeny, the systematic placements of four genera in Polygonaceae, as well as the infra-generic relationships of Atraphaxis and Calligonum within Atraphaxideae. Five chloroplast genes, atpB-rbcL, psbA-trnH, trnL-tmF, psbK-psbl, and rbcL of Atraphaxis, Calligonum, Pteropyrum, and Parapteropyrum were sequenced. The non-monophyly of Atraphaxideae was confirmed. Atraphaxis and Calligonum, respectively, formed a monophyletic group that was well supported. Calligonum is closely related to Pteropyrum; Atraphaxis is sister to Polygonum s. str. and Parapteropyrum is allied with Fagopyrum. Although the morphology suggested the four genera should form a tribe, the molecular data indicated Atraphaxideae was not one monophyletic group. The clades identified within Atraphaxis corresponded well with the current sectional classification based on morphological features. As for Cal- ligonum, Medusa was identified as a non-monophyletic section.展开更多
基金supported by the China National Key Basic Research Programs (2012FY111500, 2014CB954201)CAS Important Direction for Knowledge Innovation Project (KZCX2-EW-305)Xinjiang Institute of Ecology and Geography, CAS
文摘Atraphaxis has approximately 25 species and a distribution center in Central Asia. It has been previously used to hypothesize an origin from montane forest. We sampled 18 species covering three sections within the genus and sequenced five cpDNA spacers, atpB -rbcL, psbK -psbI, psbA -trnH, rbcL, and trnL -trnF. BEAST was used to reconstruct phylogenetic relationship and time divergences, and S-DIVA and Lagrange were used, based on distribution area and ecotype data, for reconstruction of ancestral areas and events. Our results appear compatible with designation of three taxonomic sections within the genus. The generic stem and crown ages were Eocene, approximately 47 Ma, and Oligocene 27 Ma,respectively. The origin of Atraphaxis is confirmed as montane,with an ancestral area consisting of the Junggar Basin and uplands of the Pamir-Tianshan-Alatau-Altai mountain chains,and ancestral ecotype of montane forest. Two remarkable paleogeographic events, shrinkage of the inland Paratethys Sea at the boundary of the late Oligocene and early Miocene, and the time intervals of cooling and drying of global climate from24（22） Ma onward likely facilitated early diversification of Atraphaxis, while rapid uplift of the Tianshan Mountains during the late Miocene may have promoted later diversification.
基金supported by Chinese Academy of Sciences Important Direction for Knowledge Innovation Project (KZCX2-EW-305),Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences
文摘Traditionally, Atraphaxis, Calligonum, Pteropyrum and Parapteropyrum are included in the tribe Atraphxideae. Recently, sequence data has revealed that this tribe is not monophyletic. The structure of the tribe was examined by adding more taxa and sequences to clarify the congruence between morphology and molecular phylogeny, the systematic placements of four genera in Polygonaceae, as well as the infra-generic relationships of Atraphaxis and Calligonum within Atraphaxideae. Five chloroplast genes, atpB-rbcL, psbA-trnH, trnL-tmF, psbK-psbl, and rbcL of Atraphaxis, Calligonum, Pteropyrum, and Parapteropyrum were sequenced. The non-monophyly of Atraphaxideae was confirmed. Atraphaxis and Calligonum, respectively, formed a monophyletic group that was well supported. Calligonum is closely related to Pteropyrum; Atraphaxis is sister to Polygonum s. str. and Parapteropyrum is allied with Fagopyrum. Although the morphology suggested the four genera should form a tribe, the molecular data indicated Atraphaxideae was not one monophyletic group. The clades identified within Atraphaxis corresponded well with the current sectional classification based on morphological features. As for Cal- ligonum, Medusa was identified as a non-monophyletic section.
