陷入灭绝旋涡？衰退脊椎动物种群中的强大遗传效应。

BACKGROUND

Inbreeding and loss of genetic diversity are expected to increase the extinction risk of small populations, but detailed tests in natural populations are scarce. We combine long-term population and fitness data with those from two types of molecular markers to examine the role of genetic effects in a declining metapopulation of southern dunlins Calidris alpina schinzii, an endangered shorebird.

RESULTS

The decline is associated with increased pairings between related individuals, including close inbreeding (as revealed by both field observations of parentage and molecular markers). Furthermore, reduced genetic diversity seems to affect individual fitness at several life stages. Higher genetic similarity between mates correlates negatively with the pair's hatching success. Moreover, offspring produced by related parents are more homozygous and suffer from increased mortality during embryonic development and possibly also after hatching.

CONCLUSIONS

Our results demonstrate strong genetic effects in a rapidly declining population, emphasizing the importance of genetic factors for the persistence of small populations.

背景

近亲繁殖和遗传多样性的丧失预计会增加小种群的灭绝风险，但在自然种群中对这一现象进行详细测试的情况较为少见。我们结合了长期的种群和适应度数据以及两种类型的分子标记，来研究遗传效应在一个不断减少的南方黑腹滨鹬 Calidris alpina schinzii 异地种群中的作用，这是一种濒危的滨鸟。

结果

种群数量的减少与个体间亲缘关系配对的增加有关，包括近亲繁殖（通过对亲子关系的实地观察和分子标记都揭示了这一点）。此外，遗传多样性的减少似乎会影响个体在多个生命阶段的适应度。配偶之间更高的遗传相似性与孵化成功率呈负相关。此外，由亲缘关系的亲鸟所产的后代更纯合，在胚胎发育和可能在孵化后都面临更高的死亡率。