The genes of the major histocompatibility complex(MHC) encode cell surface proteins that are essential for adaptive immunity. MHC genes show the most prominent genetic diversity in vertebrates,reflecting the adaptatio...The genes of the major histocompatibility complex(MHC) encode cell surface proteins that are essential for adaptive immunity. MHC genes show the most prominent genetic diversity in vertebrates,reflecting the adaptation of populations to their evolving environment, population survival and reproduction. In the present study, we used nextgeneration sequencing(NGS) to study the loci polymorphism of exon 3 of the MHC class Ⅰ genes in an ovoviviparous skink, the many-lined sun skink,Eutropis multifasciata and five other species of Scincidae, to quantify genetic variation. In addition,we genotyped the same MHC class Ⅰ genes of E.multifasciata using clone sequencing, to directly compare the effectiveness of both analytical techniques for MHC genotyping. NGS detected 20MHC class Ⅰ alleles in E. multifasciata, and 2 to 15 alleles in the other five Scincidae species. However,clone sequencing detected only 15 of those MHC class Ⅰ alleles in E. multifasciata. In addition, transspecies polymorphism of MHC class Ⅰ genes was studied by constructing a phylogenetic tree using the gene sequences obtained by NGS. Phylogenetic analysis revealed that MHC class I alleles were shared among different species of Scincidae with trans-species polymorphism, and did not exhibit specific genealogical inheritance. These results have important implications for understanding polymorphism interspecies diversity in the MHC genes of Scincidae, and the evolution of the MHC more broadly.展开更多
Detailed information on venom yield is helpful in preparing antivenoms and treating snakebites, but such information is lacking for many species of venomous snakes. The Chinese cobra(Naja atra) is a large sized, venom...Detailed information on venom yield is helpful in preparing antivenoms and treating snakebites, but such information is lacking for many species of venomous snakes. The Chinese cobra(Naja atra) is a large sized, venomous snake commonly found in southeastern China, where it causes a heavy burden of snakebites. To examine the effects of various factors(morphology, sex, age, season, and geographical origin) on the venom yield in this snake, we collected venom samples of 446 individuals(426 adults and 20 neonates) from 10 populations of N. atra over an eightyear period. We used two variables, lyophilized venom mass(venom yield) and solid content of venom(% solids), to quantify the venom yield. We used linear regression analysis to check if venom yield was related to morphological factors, one-way ANOVA and one-way ANCOVA to detect the sexual, ontogenetic, and geographic variation in venom yield, and repeated-measures ANOVA to examine seasonal shifts in venom yield. Our results indicate that venom yield of N. atra is positively related to the morphological traits examined, with male snakes expelling more venom than females. Venom yield in N. atra was age-related, with elder snakes always expelling more venom than younger ones. Geographic variation in venom yield was also observed, while seasonal variation was not. The solid content of venom was lower in males than in females, but this was not related to morphology, season, age, or geography. Our findings suggest that venom yield in N. atra is influenced by multiple factors, as well as by the interactions among these factors.展开更多
Phylogeographic studies of Eremias lizards （Lacertidae） in East Asia have been limited, and the impact of major climatic events on their population dynamics remains poorly known. This study aimed to investigate popu...Phylogeographic studies of Eremias lizards （Lacertidae） in East Asia have been limited, and the impact of major climatic events on their population dynamics remains poorly known. This study aimed to investigate population histories and refugia during the Last Glacial Maximum of two sympatric Eremias lizards （E. argus and E. brenchleyi） inhabiting northern China. We sequenced partial mitochondrial DNA from the ND4 gene for 128 individuals of E. argus from nine localities, and 46 individuals of E. brenchleyi from five localities. Forty-four ND4 haplotypes were determined from E. argus samples, and 33 from E. brenchleyi samples. Population expansion events began about 0.0044 Ma in E. argus, and 0.031 Ma in E. brenchleyi. The demographic history of E. brenchleyi indicates a long-lasting population decline since the most recent common ancestor, while that of E. argus indicates a continuous population growth. Among-population structure was significant in both species, and there were multiple refugia across their range. Intermittent gene flow occurred among expanded populations across multiple refugia during warmer phases of the glacial period, and this may explain why the effective population size has remained relatively stable in E. brenchleyi and grown in E. argus.展开更多
Research on the ecological effect of microronamentations on the scale surface in reptiles has been carried out over the past few decades.It is found that the microornamentation pattern in reptiles is related to their ...Research on the ecological effect of microronamentations on the scale surface in reptiles has been carried out over the past few decades.It is found that the microornamentation pattern in reptiles is related to their habitats.This study examined the wettability on scale surface,as well as the differences in microornamentation on ventral scales from the mid-body region in three snake species,Hypsiscopus plumbea(aquatic),Oocatochus rufodorsata(semi-aquatic) and Elaphe carinata(terricolous).Moreover,the scale specimens were metallized and analyzed using scanning electron microscopy.Our results showed that there are microornamentations on the ventral scale surfaces of the tested species,which showed interspecific differences.To be specific,the aquatic snake shows the narrow,fine and regular denticulations which are connected to reduce friction and dirt shedding.By contrast,the terrestrial snake acquired the wider and shorter denticulation which would render more friction during locomotion but it shows greater water resistance to improve the capacity of dirt shedding and compensate for the disadvantage of short and wide denticulations.Additionally,the denticulation characteristics of the semi-aquatic snake fell in between those of aquatic and terrestrial snakes.Therefore,it is deduced in this study that the ventral scale microornamentations in snakes contribute to ecological adaptation to their preferential microhabitats.展开更多
Theroleof nicheevolution(niche conservatism or niche divergence)in lineage diversification is a poorly studied area.The Chinese cobra Naja atra(Elapidae)has diverged into three lineages:Lineage E in eastern China,Line...Theroleof nicheevolution(niche conservatism or niche divergence)in lineage diversification is a poorly studied area.The Chinese cobra Naja atra(Elapidae)has diverged into three lineages:Lineage E in eastern China,Lineage S in southern China and Vietnam,and Lineage W in western China.However,whether the ecological niche is conserved or divergent among these three lineages is unknown.In the present study,we used ecological niche models in geographical space to study the ecological differences among lineages.We compared the niche overlap in environmental space to test niche conservatism and niche divergence.Our results showed that the three lineages of N.atra shared an ecological niche space between Lineages E and S/W,with the climatic niches of Lineages S and W representing a specialized fraction of the climatic niche of Lineage E.We speculated that the niche divergence between Lineages S and W was a consequence of geographical barriers limitinggeneflow.Ourstudyprovides evidence for lineage diversification associated with both geographical isolation and climatic niche evolution,suggesting that early niche divergence between Lineages S and W,followed by niche conservatism,causes niche divergence among lineages.展开更多
The red-backed ratsnake（Elaphe rufodorsata） is widely distributed in East Asia, especially China. This species is a common snake in plain river network region. In the past several decades, E. rufodorsata has dramati...The red-backed ratsnake（Elaphe rufodorsata） is widely distributed in East Asia, especially China. This species is a common snake in plain river network region. In the past several decades, E. rufodorsata has dramatically declined due to the effect of human activities and over hunting for traditional Chinese medicine. We developed nine species-specific microsatellite loci in 190 individuals collected from Huzhou, Zhejiang province in China. These markers revealed a high degree of genetic diversity（13–41 alleles per locus） and heterozygosity（H O ranged from 0.266 to 0.941, and H E ranged from 0.851 to 0.937）. No locus exhibited significant deviations from Hardy–Weinberg equilibrium. There was no evidence of linkage disequilibrium among pairs of loci. These microsatellite markers were described in our study will be valuable tools for the long term management and population-level studies（e.g. the population structure, genetic diversity and variation, individual paternity and evolutionary history） of the species.展开更多
We reported data on thermal preference, thermal tolerance and the thermal dependence of digestive performance for two Phrynocephalus lizards （P. frontalis and P. versicolor）, and compared data among lizards so far s...We reported data on thermal preference, thermal tolerance and the thermal dependence of digestive performance for two Phrynocephalus lizards （P. frontalis and P. versicolor）, and compared data among lizards so far studied worldwide. Mean values for selected body temperature （Tsel） and critical thermal maximum （CTMax） were greater in P versicolor, whereas mean values for critical thermal minimum （CTMin） did not differ between the two species. The two lizards differed in food intake, but not in food passage time, apparent digestive coefficient （ADC） and assimilation efficiency （AE）, across the experimental tem- peratures. Four general conclusions can be drawn from published data. Firstly, thermal preference and thermal tolerance differ among lizards differing in distribution, temporal activity pattern and habitat use. Lizards in thermally more variable regions are better able to tolerate low and high temperatures. Diurnal lizards generally select higher body temperatures than nocturnal lizards, and lizards using habitats with direct sun exposure generally selected higher body temperatures and are better able to tolerate high temperatures. Secondly, CTMax is positively correlated with Tsel. Lizards more likely exposed to extremely high temperatures while active select higher body temperatures than those using shaded habitats. Thirdly, the effects of body temperature on food intake, food passage time, ADC and AE differ among lizards, but it seems to be common among lizards that ADC and AE are less thermally sensitive than food intake and food passage time. Lastly, ADC is dependent on the type of food ingested, with insectivorous lizards digesting food more efficiently than herbivorous lizards展开更多
基金This work was supported by grants from the National Natural Science Foundation of China(32171495 and 31971414)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘The genes of the major histocompatibility complex(MHC) encode cell surface proteins that are essential for adaptive immunity. MHC genes show the most prominent genetic diversity in vertebrates,reflecting the adaptation of populations to their evolving environment, population survival and reproduction. In the present study, we used nextgeneration sequencing(NGS) to study the loci polymorphism of exon 3 of the MHC class Ⅰ genes in an ovoviviparous skink, the many-lined sun skink,Eutropis multifasciata and five other species of Scincidae, to quantify genetic variation. In addition,we genotyped the same MHC class Ⅰ genes of E.multifasciata using clone sequencing, to directly compare the effectiveness of both analytical techniques for MHC genotyping. NGS detected 20MHC class Ⅰ alleles in E. multifasciata, and 2 to 15 alleles in the other five Scincidae species. However,clone sequencing detected only 15 of those MHC class Ⅰ alleles in E. multifasciata. In addition, transspecies polymorphism of MHC class Ⅰ genes was studied by constructing a phylogenetic tree using the gene sequences obtained by NGS. Phylogenetic analysis revealed that MHC class I alleles were shared among different species of Scincidae with trans-species polymorphism, and did not exhibit specific genealogical inheritance. These results have important implications for understanding polymorphism interspecies diversity in the MHC genes of Scincidae, and the evolution of the MHC more broadly.
基金supported by grants from the National Natural Science Foundation of China (31101635, 31471995 and 31770428)Zhejiang Provincial Foundation of Science (LY14C030007)Open Fund of Jiangsu Key Laboratory for Biodiversity and Biotechnology
文摘Detailed information on venom yield is helpful in preparing antivenoms and treating snakebites, but such information is lacking for many species of venomous snakes. The Chinese cobra(Naja atra) is a large sized, venomous snake commonly found in southeastern China, where it causes a heavy burden of snakebites. To examine the effects of various factors(morphology, sex, age, season, and geographical origin) on the venom yield in this snake, we collected venom samples of 446 individuals(426 adults and 20 neonates) from 10 populations of N. atra over an eightyear period. We used two variables, lyophilized venom mass(venom yield) and solid content of venom(% solids), to quantify the venom yield. We used linear regression analysis to check if venom yield was related to morphological factors, one-way ANOVA and one-way ANCOVA to detect the sexual, ontogenetic, and geographic variation in venom yield, and repeated-measures ANOVA to examine seasonal shifts in venom yield. Our results indicate that venom yield of N. atra is positively related to the morphological traits examined, with male snakes expelling more venom than females. Venom yield in N. atra was age-related, with elder snakes always expelling more venom than younger ones. Geographic variation in venom yield was also observed, while seasonal variation was not. The solid content of venom was lower in males than in females, but this was not related to morphology, season, age, or geography. Our findings suggest that venom yield in N. atra is influenced by multiple factors, as well as by the interactions among these factors.
基金supported by grants from Chinese Ministry of Education (20070319006)the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Phylogeographic studies of Eremias lizards （Lacertidae） in East Asia have been limited, and the impact of major climatic events on their population dynamics remains poorly known. This study aimed to investigate population histories and refugia during the Last Glacial Maximum of two sympatric Eremias lizards （E. argus and E. brenchleyi） inhabiting northern China. We sequenced partial mitochondrial DNA from the ND4 gene for 128 individuals of E. argus from nine localities, and 46 individuals of E. brenchleyi from five localities. Forty-four ND4 haplotypes were determined from E. argus samples, and 33 from E. brenchleyi samples. Population expansion events began about 0.0044 Ma in E. argus, and 0.031 Ma in E. brenchleyi. The demographic history of E. brenchleyi indicates a long-lasting population decline since the most recent common ancestor, while that of E. argus indicates a continuous population growth. Among-population structure was significant in both species, and there were multiple refugia across their range. Intermittent gene flow occurred among expanded populations across multiple refugia during warmer phases of the glacial period, and this may explain why the effective population size has remained relatively stable in E. brenchleyi and grown in E. argus.
基金supported by grants from Natural Science Foundation of China(31200283 and 31770443)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) of Jiangsu Higher Education Institutions。
文摘Research on the ecological effect of microronamentations on the scale surface in reptiles has been carried out over the past few decades.It is found that the microornamentation pattern in reptiles is related to their habitats.This study examined the wettability on scale surface,as well as the differences in microornamentation on ventral scales from the mid-body region in three snake species,Hypsiscopus plumbea(aquatic),Oocatochus rufodorsata(semi-aquatic) and Elaphe carinata(terricolous).Moreover,the scale specimens were metallized and analyzed using scanning electron microscopy.Our results showed that there are microornamentations on the ventral scale surfaces of the tested species,which showed interspecific differences.To be specific,the aquatic snake shows the narrow,fine and regular denticulations which are connected to reduce friction and dirt shedding.By contrast,the terrestrial snake acquired the wider and shorter denticulation which would render more friction during locomotion but it shows greater water resistance to improve the capacity of dirt shedding and compensate for the disadvantage of short and wide denticulations.Additionally,the denticulation characteristics of the semi-aquatic snake fell in between those of aquatic and terrestrial snakes.Therefore,it is deduced in this study that the ventral scale microornamentations in snakes contribute to ecological adaptation to their preferential microhabitats.
基金supported by grants from the National Natural Science Foundation of China (32071493, 31971414 and 31770443)Finance Science and Technology Project of Hainan Province (ZDYF2018219)
文摘Theroleof nicheevolution(niche conservatism or niche divergence)in lineage diversification is a poorly studied area.The Chinese cobra Naja atra(Elapidae)has diverged into three lineages:Lineage E in eastern China,Lineage S in southern China and Vietnam,and Lineage W in western China.However,whether the ecological niche is conserved or divergent among these three lineages is unknown.In the present study,we used ecological niche models in geographical space to study the ecological differences among lineages.We compared the niche overlap in environmental space to test niche conservatism and niche divergence.Our results showed that the three lineages of N.atra shared an ecological niche space between Lineages E and S/W,with the climatic niches of Lineages S and W representing a specialized fraction of the climatic niche of Lineage E.We speculated that the niche divergence between Lineages S and W was a consequence of geographical barriers limitinggeneflow.Ourstudyprovides evidence for lineage diversification associated with both geographical isolation and climatic niche evolution,suggesting that early niche divergence between Lineages S and W,followed by niche conservatism,causes niche divergence among lineages.
基金supported by grants from Natural Science Foundation of China (31200283,31272294 and 31270571)the Priority Academic Program Development of Jiangsu Higher Education Institutions,Teaching Reform Research of Nanjing Normal University (2014-61)Postgraduate Research Innovation Projects (KYLX_0716) of Nanjing Normal University
文摘The red-backed ratsnake（Elaphe rufodorsata） is widely distributed in East Asia, especially China. This species is a common snake in plain river network region. In the past several decades, E. rufodorsata has dramatically declined due to the effect of human activities and over hunting for traditional Chinese medicine. We developed nine species-specific microsatellite loci in 190 individuals collected from Huzhou, Zhejiang province in China. These markers revealed a high degree of genetic diversity（13–41 alleles per locus） and heterozygosity（H O ranged from 0.266 to 0.941, and H E ranged from 0.851 to 0.937）. No locus exhibited significant deviations from Hardy–Weinberg equilibrium. There was no evidence of linkage disequilibrium among pairs of loci. These microsatellite markers were described in our study will be valuable tools for the long term management and population-level studies（e.g. the population structure, genetic diversity and variation, individual paternity and evolutionary history） of the species.
文摘We reported data on thermal preference, thermal tolerance and the thermal dependence of digestive performance for two Phrynocephalus lizards （P. frontalis and P. versicolor）, and compared data among lizards so far studied worldwide. Mean values for selected body temperature （Tsel） and critical thermal maximum （CTMax） were greater in P versicolor, whereas mean values for critical thermal minimum （CTMin） did not differ between the two species. The two lizards differed in food intake, but not in food passage time, apparent digestive coefficient （ADC） and assimilation efficiency （AE）, across the experimental tem- peratures. Four general conclusions can be drawn from published data. Firstly, thermal preference and thermal tolerance differ among lizards differing in distribution, temporal activity pattern and habitat use. Lizards in thermally more variable regions are better able to tolerate low and high temperatures. Diurnal lizards generally select higher body temperatures than nocturnal lizards, and lizards using habitats with direct sun exposure generally selected higher body temperatures and are better able to tolerate high temperatures. Secondly, CTMax is positively correlated with Tsel. Lizards more likely exposed to extremely high temperatures while active select higher body temperatures than those using shaded habitats. Thirdly, the effects of body temperature on food intake, food passage time, ADC and AE differ among lizards, but it seems to be common among lizards that ADC and AE are less thermally sensitive than food intake and food passage time. Lastly, ADC is dependent on the type of food ingested, with insectivorous lizards digesting food more efficiently than herbivorous lizards
