The effect of total dissolved gas （TDG） supersaturation on fish living downstream of dams is one of the main ecological risks of high dam construction. A strategy for mitigating the negative effects is needed urgent...The effect of total dissolved gas （TDG） supersaturation on fish living downstream of dams is one of the main ecological risks of high dam construction. A strategy for mitigating the negative effects is needed urgently since many high dams are under construction in the upper reaches of the Yangtze River in China. Experiments on the hatching process of David＇s schizothoracin were carried out and the results show that the hatching rate decreased with increasing TDG levels, and that most eggs hatched within a very short time in the higher TDG saturation groups. By using a stereomicroscope, damages to the head, yolk sac, body, anus, etc. were found in larvae which hatched in TDG supersaturated water. Results show that the lesion rate increased with increasing TDG levels. Furthermore, 7-d-old David＇s schizothoracin were exposed to TDG supersaturated water levels of 100%, 105%, 110%, 115%, 120%, 125%, 130%, 135%, and 140% for testing their tolerance to TDG supersaturation. We found that the median lethal concentrations （LC50） for 13, 14, 20, 35, 52, 73, and 96 h exposure were 138%, 138%, 134%, 130%, 129%, 128%, and 126%, respectively. The median lethal times （LTs0） were 7.49, 11.04, 19.25, and 35.38 h for exposure to water with TDG levels of 145%, 140%, 135%, and 130%, respectively.展开更多
Schizothoracine fishes are distributed in the Nagqu region,which is the hinterland of the Tibetan Plateau.They have adapted to the cold and strongly ultraviolet environment of the plateau and show diverse morphologies...Schizothoracine fishes are distributed in the Nagqu region,which is the hinterland of the Tibetan Plateau.They have adapted to the cold and strongly ultraviolet environment of the plateau and show diverse morphologies,which makes them ideal for studying the relationship between phenotype and environment.However,traditional morphological measurements are time consuming and labor costly.In this study,we propose a deep-learningbased method for acquiring high-throughput phenotypic data of fishes,including image dataset construction of schizothoracine fishes(including front,side,and top views),fish keypoint detection based on the You Only Look Once(YOLO)model,and reconstruction of 2D and 3D keypoint coordinates based on multiple views.A total of 7050 phenotypic data points consisting of keypoint distances and angles were constructed for each fish and were highly correlated(>0.98)with the corresponding data measured manually.We obtained phenotypic data for a total of 525 fishes from three schizothoracine fish groups inhabiting riverine,lacustrine,and river–lake transitional environments using the proposed phenotypic data acquisition method.We employed a random forest algorithm to classify the groups,achieving a classification accuracy of 96%,and identified 15 morphometric indices that exhibited statistically significant differences.,of which 6 were related to head morphology,6 related to body shape,and 3 related to tail morphology,based on the random forest algorithm.Specifically,river-living schizothoracine fishes showed a blunt head,robust body,and elongated caudal peduncle which may reflect adaptations to the turbulence of the river,while the lake-living schizothoracine fishes have the opposite effect.Schizothoracine fishes at the river–lake transitional zones were phenotypically characterized as being in the middle of the two phenotypes,and these presumably reflect adaptations to their lake habitat.This study provides a methodological reference for obtaining high-throughput phenotypic data on fish and a theoretical basis for understanding the adaptation of very high-altitude schizothoracine fishes to their environment.展开更多
Origin and diversification of the Tibetan polyploid cyprinids(schizothoracins) may help us to explore relationships between diversification of the cyprinids and the Tibetan Plateau uplift. Cyprininae phylogeny was ana...Origin and diversification of the Tibetan polyploid cyprinids(schizothoracins) may help us to explore relationships between diversification of the cyprinids and the Tibetan Plateau uplift. Cyprininae phylogeny was analyzed using mitochondrial and nuclear DNA sequences to trace origins of polyploidy and diversifications of schizothoracins. Ancestral states reconstruction for ploidy levels indicated that the Cyprininae was diploid origin and the schizothoracin clades tetraploid origins. There were two diversification rate shifts along with diversification of the cyprinine fishes in response to the Tibetan uplift. The unusual diversification shifts were located to branches subtending the clades of Tibetan polyploid cyprinids. Our analyses suggested that(i) phylogeny of Cyprininae recovered two independent origins of the Tibetan polyploidy schizothoracins;(ii) diversifications of the schizothoracins were closely related to the Neogene uplift of the Tibetan plateau in the following ways: the relatively ancient Late Oligocene-Middle Miocene adaptive radiation may be associated with the uplift of the southern Tibet and Himalaya; the Middle Miocene-Early Pleistocene lineage-specific diversification broadly coincident with major phase of the Neogene Tibetan uplift; and the most recent Pleistocene diversification shift in Schizothorax closely coincident with the successive Kunlun-Huanghe and Gonghe movements of the Tibetan uplift and the glaciation-induced climate oscillations on the plateau.展开更多
Fishes harbor a huge resource of phenotypic diversity and are useful for understanding the genetic basis of morphological variation.However,it is difficult to transfer classical genetic mapping to most non-model speci...Fishes harbor a huge resource of phenotypic diversity and are useful for understanding the genetic basis of morphological variation.However,it is difficult to transfer classical genetic mapping to most non-model species.In this study,we performed a comparative sequence analysis of Fgfr1a to first interpret the evolution of this candidate scale-loss gene in 15 schizothoracine fishes with various scale phenotypes.While considerable amino acid(AA)substitutions were observed,molecular evolution analysis indicates that the overall coding regions were subject to functional constraint.We also identified extra copies of Fgfr1a in 4 scale-loss fishes and detected accelerated evolution in one AA substitution specific to these duplicates.We speculate that Fgfr1a had accumulated mutations in the ancestral lineage of scale-loss schizothoracine fishes before experiencing duplication events,which was further followed by the diversification of species.In silico mutation analysis predicted deleterious effects of the mutations while no disruptive molecular mechanism was detected.Collectively,our results highlight the important role of Fgfr1a gene in the adaptive evolution of schizothoracine fishes during their radiation in the Qinghai-Tibetan Plateau.展开更多
基金Project (No. 50979063) supported by the National Natural Science Foundation of China
文摘The effect of total dissolved gas （TDG） supersaturation on fish living downstream of dams is one of the main ecological risks of high dam construction. A strategy for mitigating the negative effects is needed urgently since many high dams are under construction in the upper reaches of the Yangtze River in China. Experiments on the hatching process of David＇s schizothoracin were carried out and the results show that the hatching rate decreased with increasing TDG levels, and that most eggs hatched within a very short time in the higher TDG saturation groups. By using a stereomicroscope, damages to the head, yolk sac, body, anus, etc. were found in larvae which hatched in TDG supersaturated water. Results show that the lesion rate increased with increasing TDG levels. Furthermore, 7-d-old David＇s schizothoracin were exposed to TDG supersaturated water levels of 100%, 105%, 110%, 115%, 120%, 125%, 130%, 135%, and 140% for testing their tolerance to TDG supersaturation. We found that the median lethal concentrations （LC50） for 13, 14, 20, 35, 52, 73, and 96 h exposure were 138%, 138%, 134%, 130%, 129%, 128%, and 126%, respectively. The median lethal times （LTs0） were 7.49, 11.04, 19.25, and 35.38 h for exposure to water with TDG levels of 145%, 140%, 135%, and 130%, respectively.
基金funded by the National Natural Science Foundation of China(NSFC)Joint Fund Priority Support Program(U23A20249)the“Special fund for youth team of the Southwest University”(SWUXJPY202302)+3 种基金the“National Talent Research Grant for 2023”(5330500953)National Natural Science Foundation of China(32072980)Chongqing Innovation Program for Graduate Research(CYB240106)the National Key R&D Program of China(grant no.2024YFD1200703).
文摘Schizothoracine fishes are distributed in the Nagqu region,which is the hinterland of the Tibetan Plateau.They have adapted to the cold and strongly ultraviolet environment of the plateau and show diverse morphologies,which makes them ideal for studying the relationship between phenotype and environment.However,traditional morphological measurements are time consuming and labor costly.In this study,we propose a deep-learningbased method for acquiring high-throughput phenotypic data of fishes,including image dataset construction of schizothoracine fishes(including front,side,and top views),fish keypoint detection based on the You Only Look Once(YOLO)model,and reconstruction of 2D and 3D keypoint coordinates based on multiple views.A total of 7050 phenotypic data points consisting of keypoint distances and angles were constructed for each fish and were highly correlated(>0.98)with the corresponding data measured manually.We obtained phenotypic data for a total of 525 fishes from three schizothoracine fish groups inhabiting riverine,lacustrine,and river–lake transitional environments using the proposed phenotypic data acquisition method.We employed a random forest algorithm to classify the groups,achieving a classification accuracy of 96%,and identified 15 morphometric indices that exhibited statistically significant differences.,of which 6 were related to head morphology,6 related to body shape,and 3 related to tail morphology,based on the random forest algorithm.Specifically,river-living schizothoracine fishes showed a blunt head,robust body,and elongated caudal peduncle which may reflect adaptations to the turbulence of the river,while the lake-living schizothoracine fishes have the opposite effect.Schizothoracine fishes at the river–lake transitional zones were phenotypically characterized as being in the middle of the two phenotypes,and these presumably reflect adaptations to their lake habitat.This study provides a methodological reference for obtaining high-throughput phenotypic data on fish and a theoretical basis for understanding the adaptation of very high-altitude schizothoracine fishes to their environment.
基金supported by the National Natural Science Foundation of China(31272290)
文摘Origin and diversification of the Tibetan polyploid cyprinids(schizothoracins) may help us to explore relationships between diversification of the cyprinids and the Tibetan Plateau uplift. Cyprininae phylogeny was analyzed using mitochondrial and nuclear DNA sequences to trace origins of polyploidy and diversifications of schizothoracins. Ancestral states reconstruction for ploidy levels indicated that the Cyprininae was diploid origin and the schizothoracin clades tetraploid origins. There were two diversification rate shifts along with diversification of the cyprinine fishes in response to the Tibetan uplift. The unusual diversification shifts were located to branches subtending the clades of Tibetan polyploid cyprinids. Our analyses suggested that(i) phylogeny of Cyprininae recovered two independent origins of the Tibetan polyploidy schizothoracins;(ii) diversifications of the schizothoracins were closely related to the Neogene uplift of the Tibetan plateau in the following ways: the relatively ancient Late Oligocene-Middle Miocene adaptive radiation may be associated with the uplift of the southern Tibet and Himalaya; the Middle Miocene-Early Pleistocene lineage-specific diversification broadly coincident with major phase of the Neogene Tibetan uplift; and the most recent Pleistocene diversification shift in Schizothorax closely coincident with the successive Kunlun-Huanghe and Gonghe movements of the Tibetan uplift and the glaciation-induced climate oscillations on the plateau.
基金supported by the grants from the Knowledge Innovation Project(KSCX2-EW-J-26)Youth Innovation Promotion Association Foundation of the Chinese Academy of Sciences.
文摘Fishes harbor a huge resource of phenotypic diversity and are useful for understanding the genetic basis of morphological variation.However,it is difficult to transfer classical genetic mapping to most non-model species.In this study,we performed a comparative sequence analysis of Fgfr1a to first interpret the evolution of this candidate scale-loss gene in 15 schizothoracine fishes with various scale phenotypes.While considerable amino acid(AA)substitutions were observed,molecular evolution analysis indicates that the overall coding regions were subject to functional constraint.We also identified extra copies of Fgfr1a in 4 scale-loss fishes and detected accelerated evolution in one AA substitution specific to these duplicates.We speculate that Fgfr1a had accumulated mutations in the ancestral lineage of scale-loss schizothoracine fishes before experiencing duplication events,which was further followed by the diversification of species.In silico mutation analysis predicted deleterious effects of the mutations while no disruptive molecular mechanism was detected.Collectively,our results highlight the important role of Fgfr1a gene in the adaptive evolution of schizothoracine fishes during their radiation in the Qinghai-Tibetan Plateau.
