皱纹盘鲍野生与养殖群体微卫星标记遗传变异研究

Microsatellites Analysis on Genetic Variation Between Wild and Cultured Populations of Pacific Abalone(Haliotis discus hannai)

采用7个微卫星标记对辽宁大连、山东烟台、荣城、崂山和胶南5个皱纹盘鲍养殖群体，以及山东长岛、荣城、日本岩手、韩国仁川4个皱纹盘鲍野生群体进行了群体遗传多样性与遗传分化的研究。结果表明，从等位基因数与杂合度上分析，养殖群体（N=8．0～9．4，He=0．754～0．787）遗传多样性显著低于野生群体（N=11．3～15.0，He=0．821～0．866）；等位基因频率分布揭示出野生群体中一些稀有等位基因在养殖群体中有所丢失；亲鲍选用数量少与性别比例不均衡可能是产生养殖群体中遗传多样性显著减少的原因。通过对等位基因频率比较分析，5个养殖群体之间以及养殖群体与野生群体之间观察到显著差异的Fst与Rst值，野生群体之间日本群体Fst与Rst值与其他3个野生群体差异显著，群体间存在遗传分化；养殖群体间遗传距离与地理距离不相关，可能是皱纹盘鲍育苗过程中亲鲍和苗种频繁交流所造成的结果；日本群体与其他3个野生群体间存在显著遗传分化与皱纹盘鲍短暂的浮游期与有限的扩散能力有关。

Genetic diversity of five cultured and four wild populations of the Haliotis discus hannai from northern China and east Asia was analysed using seven microsatellite markers, and the degrees of genetic differentiation between them were compared. The allelic diversity in terms of number of alleles per locus and expected heterozygosities in cultured populations （N = 8.0 - 9.4, He = 0. 754 - 0. 787） was considerably lower than that found in the wild populations （N = 11.3- 15.0, He = 0. 821 -0. 866）. Allele distributions at all seven microsatellites indicated that the cultured populations lost some rare alleles belonging to wild populations. The small number and the biased sex ratio of abalone for hatchery broodstock might be responsible for the remarkable reduction of genetic variation in the studied populations. Significant genetic differentiation among the five cultured populations, and between the cultured and wild populations, moreover, between the Japanese population and other three wild populations was detected using Fst and Rst values. However, there is no consistent relationship between the geographic and the genetic distances in the five cultured populations, suggesting the existence of exchanges of breeds and eggs between the hatcheries. Significant genetic structuring between the Japanese population and other 3 wild populations could be the result of short planktonic phase and limited diffusivity of H. discus hannai.