广东流溪河水库盔型溞(Daphnia galeata)休眠种群与现生种群的单倍型多样性和遗传分化

休眠卵库作为淡水枝角类生物与遗传信息的储藏库,从沉积物休眠卵库中萌发的枝角类对现生种群的数量与种群遗传结构有着直接的影响.分别采集流溪河水库盔型溞的现生种群和沉积物表层(0~10 cm)的休眠卵,扩增现生种群与休眠卵的线粒体细胞色素C氧化酶亚基I基因,构建了单倍型网络.休眠种群相比现生种群有着较高的单倍型多样性和核酸多样性,初期现生种群分别为0.562、0.00104,末期现生种群分别为0.726、0.00331,休眠种群分别为0.815、0.00761.流溪河盔型溞现生种群与休眠种群存在双向基因流,现生种群到休眠种群的有效迁移率为490.9,休眠种群到现生种群的有效迁移率为527.5.通过构建贝叶斯系统树验证了休眠种群和现有种群中并不存在隐种或者亚种的分化,休眠种群与现生种群之间没有出现较大的遗传分化,现生种群遗传多样性来自于休眠种群,水库的休眠种群更能反映种群真实的遗传多样性.休眠种群与现生种群之间的基因流与休眠卵库大小无关,与休眠卵的萌发有关.

Haplotype diversity and genetic differentiation of dormant and active populations of Daphnia galeata in Liuxihe Reservoir of Guangdong Province,southern China

The dormant egg bank in sediments has been regarded as a pool of species diversity and genetic information of freshwater Cladocera.Hatchings from the sediments strongly and directly affect the abundance and genetic structure of active population of Cladocera.In the present study,we sampled the active population in water column and picked up dormant eggs of Daphnia galeata in the top 10 cm of the sediment in Liuxihe Reservoir.We used cytochrome C oxidase subunit I gene to reveal the haplotype diversi-ty and genetic differentiation of active and dormant populations of Daphnia galeata in the reservoir.Our results showed the dormant population had higher haplotype diversity and nucleotide diversity than the active population.The haplotype diversity and nucleotide diversity were 0.562 and 0.00104 for the initial active population,0.726 and 0.00331 for the end active population,and 0.815 and 0.00761 for the dormant population,respectively.The coalescent calculation suggested that there was a bi-directional gene flow be-tween the active and dormant populations:the effective migration rate was 490.9 from active population to dormant population and 527.5 from dormant population to active population.We did not find hidden or subspecies differentiation in the dormant population and the active population by means of a Bayesian system tree.No significant genetic differentiation between the dormant population and the active population suggested that the genetic diversity of the active population was contributed by the dormant population.Therefore,the dormant population reflects the total genetic diversity of populations in the reservoir.The gene flow between the dor-mant and active populations was related to the hatching of dormant eggs rather than the size of the dormant eggs.