A herd of 15 Chinese elephants attracted international attention during their 2021 northward trek,motivating the government to propose establishment of an Asian elephant national park.However,planning is hampered by a...A herd of 15 Chinese elephants attracted international attention during their 2021 northward trek,motivating the government to propose establishment of an Asian elephant national park.However,planning is hampered by a lack of genetic information on the remaining populations in China.We collected DNA from 497 dung samples from all 5 populations encompassing the entire range of elephants in China and used mitochondrial and microsatellite markers to investigate their genetic and demographic structure.We identified 237 unique genotypes(153 females,84 males),representing 81%of the known population.However,the effective population size was small(28,range 25–32).Historic demographic contraction appeared to account for low haplotype diversity(Hd=0.235),but mod-erate nucleotide and nuclear diversity(π=0.6%,He=0.55)was attributable to post-bottleneck recovery involving recent population expansion plus historical gene exchange with elephants in Myanmar,Lao PDR,and Vietnam.The 5 populations fell into 3 clusters,with Nangunhe elephants differing consistently from the other 4 populations(FST=0.23);elephants from Mengyang,Simao,and Jiangcheng belonged to a single population(henceforth,MSJ),and differed from the Shangyong population(FST=0.11).Interpopulation genetic variation reflected isola-tion by distance and female-biased dispersal.Chinese elephants should be managed as 2 distinct units:Nangunhe and another combining Shangyong and MSJ;their long-term viability will require restoring geneflow between Shangyong and MSJ,and between elephants in China and neighboring countries.Our results have the potential to inform conservation planning for an iconic megafaunal species.展开更多
Differences in heavy metal tolerance among separate populations of the same species have often been interpreted as local adaptation. Persistence of differences after removing the stressor indicates that mechanisms res...Differences in heavy metal tolerance among separate populations of the same species have often been interpreted as local adaptation. Persistence of differences after removing the stressor indicates that mechanisms responsible for the increased tolerance were genetically determined. Drosophila subobscura Collin （Diptera： Drosophilidae） pop- ulations were sampled from two localities with different history of heavy metal pollution, and reared for eight generations in the laboratory on a standard medium and on media with different concentrations of lead （Pb）. To determine whether flies from different natural populations exposed to the Pb-contaminated media in the laboratory show population spe- cific variability in fitness components over generations, experimental groups with different concentrations of lead were assayed in three generations （F2, Fs, and Fs） for fecundity, de- velopmental time, and egg-to-adult viability. On the contaminated medium, fecundity was reduced in later generations and viability was increased, irrespective of the environmental origin of populations. For both populations, developmental time showed a tendency of slowing down on media with lead. Faster development was observed in later generations. Preadaptation to contamination, meaning higher fecundity, higher viability, and faster egg to adult development in all studied generations, was found in D. subobscura originating from the locality with a higher level of heavy metal pollution,展开更多
Short tandem repeats(STRs)play an essential role in forensic genetics due to their high degree of polymorphisms,wide distributions and easy detection method.In this study,allelic frequencies and forensic statistical p...Short tandem repeats(STRs)play an essential role in forensic genetics due to their high degree of polymorphisms,wide distributions and easy detection method.In this study,allelic frequencies and forensic statistical parameters of the 19 autosomal STR loci in a Kazak ethnic group were calculated,and its genetic relationships with reference populations were assessed in order to understand population structure better and enrich population genetic data for forensic practice in Chinese Kazak ethnic group.There were 226 identified alleles with the corresponding allelic frequencies ranging from 0.0008 to 0.5295 in the 628 unrelated healthy Kazak individuals in Xinjiang Uygur Autonomous Region.All autosomal STRs were conformed to the Hardy-Weinberg equilibrium after Bonferroni’s correction.The cumulative power of discrimination and the combined probability of exclusion of all the 19 autosomal STRs were 0.999999999999999999999997162 and 0.999999994484,respectively.Furthermore,the DA distances and Fixation index values of pairwise populations,principal component analysis,multidimensional scaling analysis,phylogenetic tree analysis and structure analysis were conducted to probe the genetic relationships between the Kazak group and other reference populations.The population genetic results showed that these 19 autosomal STR loci were characterised by high genetic diversities in the Kazak group.Furthermore,the studied Kazak group had close genetic relationships with the Uyghur group and the Uzbek group.The present results may facilitate understanding the genetic background of the Chinese Xinjiang Kazak group.展开更多
基金funded by the National Forestry and Grassland Administration of China,through the“Second National Survey of Terrestrial Wildlife project”(Grant No.20080131).
文摘A herd of 15 Chinese elephants attracted international attention during their 2021 northward trek,motivating the government to propose establishment of an Asian elephant national park.However,planning is hampered by a lack of genetic information on the remaining populations in China.We collected DNA from 497 dung samples from all 5 populations encompassing the entire range of elephants in China and used mitochondrial and microsatellite markers to investigate their genetic and demographic structure.We identified 237 unique genotypes(153 females,84 males),representing 81%of the known population.However,the effective population size was small(28,range 25–32).Historic demographic contraction appeared to account for low haplotype diversity(Hd=0.235),but mod-erate nucleotide and nuclear diversity(π=0.6%,He=0.55)was attributable to post-bottleneck recovery involving recent population expansion plus historical gene exchange with elephants in Myanmar,Lao PDR,and Vietnam.The 5 populations fell into 3 clusters,with Nangunhe elephants differing consistently from the other 4 populations(FST=0.23);elephants from Mengyang,Simao,and Jiangcheng belonged to a single population(henceforth,MSJ),and differed from the Shangyong population(FST=0.11).Interpopulation genetic variation reflected isola-tion by distance and female-biased dispersal.Chinese elephants should be managed as 2 distinct units:Nangunhe and another combining Shangyong and MSJ;their long-term viability will require restoring geneflow between Shangyong and MSJ,and between elephants in China and neighboring countries.Our results have the potential to inform conservation planning for an iconic megafaunal species.
文摘Differences in heavy metal tolerance among separate populations of the same species have often been interpreted as local adaptation. Persistence of differences after removing the stressor indicates that mechanisms responsible for the increased tolerance were genetically determined. Drosophila subobscura Collin （Diptera： Drosophilidae） pop- ulations were sampled from two localities with different history of heavy metal pollution, and reared for eight generations in the laboratory on a standard medium and on media with different concentrations of lead （Pb）. To determine whether flies from different natural populations exposed to the Pb-contaminated media in the laboratory show population spe- cific variability in fitness components over generations, experimental groups with different concentrations of lead were assayed in three generations （F2, Fs, and Fs） for fecundity, de- velopmental time, and egg-to-adult viability. On the contaminated medium, fecundity was reduced in later generations and viability was increased, irrespective of the environmental origin of populations. For both populations, developmental time showed a tendency of slowing down on media with lead. Faster development was observed in later generations. Preadaptation to contamination, meaning higher fecundity, higher viability, and faster egg to adult development in all studied generations, was found in D. subobscura originating from the locality with a higher level of heavy metal pollution,
文摘Short tandem repeats(STRs)play an essential role in forensic genetics due to their high degree of polymorphisms,wide distributions and easy detection method.In this study,allelic frequencies and forensic statistical parameters of the 19 autosomal STR loci in a Kazak ethnic group were calculated,and its genetic relationships with reference populations were assessed in order to understand population structure better and enrich population genetic data for forensic practice in Chinese Kazak ethnic group.There were 226 identified alleles with the corresponding allelic frequencies ranging from 0.0008 to 0.5295 in the 628 unrelated healthy Kazak individuals in Xinjiang Uygur Autonomous Region.All autosomal STRs were conformed to the Hardy-Weinberg equilibrium after Bonferroni’s correction.The cumulative power of discrimination and the combined probability of exclusion of all the 19 autosomal STRs were 0.999999999999999999999997162 and 0.999999994484,respectively.Furthermore,the DA distances and Fixation index values of pairwise populations,principal component analysis,multidimensional scaling analysis,phylogenetic tree analysis and structure analysis were conducted to probe the genetic relationships between the Kazak group and other reference populations.The population genetic results showed that these 19 autosomal STR loci were characterised by high genetic diversities in the Kazak group.Furthermore,the studied Kazak group had close genetic relationships with the Uyghur group and the Uzbek group.The present results may facilitate understanding the genetic background of the Chinese Xinjiang Kazak group.
