Eight microsatellite markers were used to analyze genetic diversity, level of inbreeding, and effective population size of spawner and recaptured populations of Chinese shrimp（Fenneropenaeus chinensis） during stock ...Eight microsatellite markers were used to analyze genetic diversity, level of inbreeding, and effective population size of spawner and recaptured populations of Chinese shrimp（Fenneropenaeus chinensis） during stock enhancement in the Bohai Bay in 2013. A total of 254 and 238 alleles were identified in the spawner and recaptured populations, respectively, and the numbers of alleles（N_a） were 8–63 and 6–60, respectively. The numbers of effective alleles（N_e） were 2.52–21.60 and 2.67–20.72, respectively. The polymorphism information content ranged from 0.529 to 0.952. The observed heterozygosity（H_o） values（0.638–0.910 and 0.712–0.927） were lower than the expected heterozygosity（H_e） values（0.603–0.954 and 0.625–0.952）, which indicated that the two populations possessed a rich genetic diversity. In 16 tests（2 populations×8 loci）, 13 tests deviated from the HardyWeinberg equilibrium. F_（is） values were positive at seven loci and the inbreeding coefficients（F） of the two populations estimated by trio ML were 13.234% and 11.603%, suggesting that there was a relatively high degree of inbreeding. A certain level of inbreeding depression had occurred in the Chinese shrimp population. F_（st） values ranged from 0 to 0.059, with a mean of 0.028, displaying a low level of genetic differentiation in the two populations. Effective population sizes（3 060.2 and 3 842.8） were higher than the minimum number suggested for retaining the evolutionary potential to adapt to new environmental conditions. For enhancement activity in 2014,the ideal number of captured shrimp spawners should have ranged from 7 686 to 19 214 to maintain genetic diversity and effective population size. Further strategies to adjust the balance of economic cost, fishing effort and ideal number of shrimp spawners to maintain a satisfactory effective population size for ensuring the sustainability of Chinese shrimp are proposed.展开更多
Covered smut, which is caused by Ustilago hordei（Pers.） Lagerh., is one of the most damaging diseases of highland barley（Hordeum vulgare Linn. var. nudum Hook. f） in Tibetan areas of China. To understand the molec...Covered smut, which is caused by Ustilago hordei（Pers.） Lagerh., is one of the most damaging diseases of highland barley（Hordeum vulgare Linn. var. nudum Hook. f） in Tibetan areas of China. To understand the molecular diversity of U. hordei, a total of 27 isolates, which were collected from highland barley plants from Tibet, Sichuan, Qinghai, and Gansu provinces/autonomous region, were analyzed using random amplified polymorphic DNA（RAPD） and simple sequence repeat（SSR） markers. Among the 100 RAPD primers used, 24 primers exhibited polymorphism. A total of 111 fragments were amplified, of which 103 were polymorphic with a polymorphic rate of 92.79%. The average observed number of alleles（Na）, effective number of alleles（Ne）, Nei＇s genetic diversity（H）, Shannon＇s information index（I） and polymorphism information content（PIC） value in the RAPD markers were 1.9279, 1.5016, 0.2974, 0.4503 and 0.6428, respectively. For the SSR markers, 40 of the 111 primer pairs exhibited polymorphism and provided a total of 119 bands, of which 109 were polymorphic and accounted for 91.60% of the total bands. The Na, Ne, H, I and PIC values of the SSR markers were 1.9160, 1.4639, 0.2757, 0.4211 and 0.4340, respectively. The similarity coefficients ranged from 0.4957 to 0.9261 with an average of 0.7028 among all the 27 isolates used. The dendrogram, which was developed based on the RAPD and SSR combined marker dataset showed that the 27 U. hordei isolates were divided into 3 clusters at similarity coefficient of 0.7314. We determined that RAPD and SSR markers can be successfully used to assess the genetic variation among U. hordei isolates. The RAPD markers revealed higher levels of genetic polymorphism than did the SSR markers in this study. There existed a moderate genetic difference among isolates. The molecular variation and differentiation was somewhat associated with geographical origin but not for all of the isolates.展开更多
基金The National Basic Research Program of China(973 Program)Adaptive Response of Fishery Species to Environmental Changes and Their Effects on Population Dynamics under contract No.2015CB453303the International Science&Technology Cooperation Program of China under contract No.2013DFA31410
文摘Eight microsatellite markers were used to analyze genetic diversity, level of inbreeding, and effective population size of spawner and recaptured populations of Chinese shrimp（Fenneropenaeus chinensis） during stock enhancement in the Bohai Bay in 2013. A total of 254 and 238 alleles were identified in the spawner and recaptured populations, respectively, and the numbers of alleles（N_a） were 8–63 and 6–60, respectively. The numbers of effective alleles（N_e） were 2.52–21.60 and 2.67–20.72, respectively. The polymorphism information content ranged from 0.529 to 0.952. The observed heterozygosity（H_o） values（0.638–0.910 and 0.712–0.927） were lower than the expected heterozygosity（H_e） values（0.603–0.954 and 0.625–0.952）, which indicated that the two populations possessed a rich genetic diversity. In 16 tests（2 populations×8 loci）, 13 tests deviated from the HardyWeinberg equilibrium. F_（is） values were positive at seven loci and the inbreeding coefficients（F） of the two populations estimated by trio ML were 13.234% and 11.603%, suggesting that there was a relatively high degree of inbreeding. A certain level of inbreeding depression had occurred in the Chinese shrimp population. F_（st） values ranged from 0 to 0.059, with a mean of 0.028, displaying a low level of genetic differentiation in the two populations. Effective population sizes（3 060.2 and 3 842.8） were higher than the minimum number suggested for retaining the evolutionary potential to adapt to new environmental conditions. For enhancement activity in 2014,the ideal number of captured shrimp spawners should have ranged from 7 686 to 19 214 to maintain genetic diversity and effective population size. Further strategies to adjust the balance of economic cost, fishing effort and ideal number of shrimp spawners to maintain a satisfactory effective population size for ensuring the sustainability of Chinese shrimp are proposed.
基金sponsored by the National Millet Crops Research and Development System, China (CARS-0712.5-A9)the National Key Technology R&D Program of China, (2014BAD07B03)the National Natural Science Foundation of China (313 71529)
文摘Covered smut, which is caused by Ustilago hordei（Pers.） Lagerh., is one of the most damaging diseases of highland barley（Hordeum vulgare Linn. var. nudum Hook. f） in Tibetan areas of China. To understand the molecular diversity of U. hordei, a total of 27 isolates, which were collected from highland barley plants from Tibet, Sichuan, Qinghai, and Gansu provinces/autonomous region, were analyzed using random amplified polymorphic DNA（RAPD） and simple sequence repeat（SSR） markers. Among the 100 RAPD primers used, 24 primers exhibited polymorphism. A total of 111 fragments were amplified, of which 103 were polymorphic with a polymorphic rate of 92.79%. The average observed number of alleles（Na）, effective number of alleles（Ne）, Nei＇s genetic diversity（H）, Shannon＇s information index（I） and polymorphism information content（PIC） value in the RAPD markers were 1.9279, 1.5016, 0.2974, 0.4503 and 0.6428, respectively. For the SSR markers, 40 of the 111 primer pairs exhibited polymorphism and provided a total of 119 bands, of which 109 were polymorphic and accounted for 91.60% of the total bands. The Na, Ne, H, I and PIC values of the SSR markers were 1.9160, 1.4639, 0.2757, 0.4211 and 0.4340, respectively. The similarity coefficients ranged from 0.4957 to 0.9261 with an average of 0.7028 among all the 27 isolates used. The dendrogram, which was developed based on the RAPD and SSR combined marker dataset showed that the 27 U. hordei isolates were divided into 3 clusters at similarity coefficient of 0.7314. We determined that RAPD and SSR markers can be successfully used to assess the genetic variation among U. hordei isolates. The RAPD markers revealed higher levels of genetic polymorphism than did the SSR markers in this study. There existed a moderate genetic difference among isolates. The molecular variation and differentiation was somewhat associated with geographical origin but not for all of the isolates.
