Hansen M M, Ruzzante D E, nielsen E E, Mensberg K L
Danish Institute for Fisheries Research, Department of Inland Fisheries, Population Genetics Laboratory, Vejlsovej 39, DK-8600 Silkeborg, Denmark.
Mol Ecol. 2000 May;9(5):583-94. doi: 10.1046/j.1365-294x.2000.00898.x.
The effects of stocking hatchery trout into wild populations were studied in a Danish river, using microsatellite and mitochondrial DNA (mtDNA) markers. Baseline samples were taken from hatchery trout and wild trout assumed to be unaffected by previous stocking. Also, samples were taken from resident and sea trout from a stocked section of the river. Genetic differentiation between the hatchery strain and the local wild population was modest (microsatellite FST = 0.06). Using assignment tests, more than 90% of individuals from the baseline samples were classified correctly. Assignment tests involving samples from the stocked river section suggested that the contribution by hatchery trout was low among sea trout (< 7%), but high (46%) among resident trout. Hybrid index analysis and a high percentage of mtDNA haplotypes specific to indigenous trout observed among resident trout that were assigned to the hatchery strain suggested that interbreeding took place between hatchery and wild trout. The latter result also indicated that male hatchery trout contributed more to interbreeding than females. We suggest that stronger selection acts against stocked hatchery trout that become anadromous compared to hatchery trout that become resident. As most resident trout are males this could also explain why gene flow from hatchery to wild trout appeared to be male biased. The results show that even despite modest differentiation at neutral loci domesticated trout may still perform worse than local populations and it is important to be aware of differential survival and reproductive success both between life-history types and between sexes.
在丹麦的一条河流中，利用微卫星和线粒体DNA（mtDNA）标记研究了向野生种群投放孵化场鳟鱼的影响。从孵化场鳟鱼和假定未受先前投放影响的野生鳟鱼中采集基线样本。此外，还从该河流投放区域的定居鳟鱼和海鳟中采集了样本。孵化场品系与当地野生种群之间的遗传分化程度适中（微卫星FST = 0.06）。通过分配测试，基线样本中超过90%的个体被正确分类。涉及投放河流区域样本的分配测试表明，孵化场鳟鱼在海鳟中的贡献较低（<7%），但在定居鳟鱼中贡献较高（46%）。杂交指数分析以及在被归为孵化场品系的定居鳟鱼中观察到的高比例本地鳟鱼特有的mtDNA单倍型表明，孵化场鳟鱼与野生鳟鱼之间发生了杂交。后一结果还表明，雄性孵化场鳟鱼在杂交中的贡献比雌性更大。我们认为，与成为定居型的孵化场鳟鱼相比，对成为溯河洄游型的投放孵化场鳟鱼的选择作用更强。由于大多数定居鳟鱼是雄性，这也可以解释为什么从孵化场到野生鳟鱼的基因流似乎偏向雄性。结果表明，即使在中性位点的分化程度适中，驯化鳟鱼的表现可能仍比当地种群差，重要的是要意识到不同生活史类型之间以及不同性别之间的生存和繁殖成功率差异。
