PDF(Pubmed)
Abstract：
In efforts to prevent extinction, resource managers are often tasked with increasing genetic diversity in a population of concern to prevent inbreeding depression or improve adaptive potential in a changing environment. The assumption that all small populations require measures to increase their genetic diversity may be unwarranted, and limited resources for conservation may be better utilized elsewhere. We test this assumption in a case study focused on the peregrine falcon (Falco peregrinus), a cosmopolitan circumpolar species with 19 named subspecies. We used whole-genome resequencing to generate over two million single nucleotide polymorphisms (SNPs) from multiple individuals of all peregrine falcon subspecies. Our analyses revealed extensive variation among subspecies, with many island-restricted and nonmigratory populations possessing lower overall genomic diversity, elevated inbreeding coefficients (F ROH)-among the highest reported, and extensive runs of homozygosity (ROH) compared to mainland and migratory populations. Similarly, the majority of subspecies that are either nonmigratory or restricted to islands show a much longer history of low effective population size (N e). While mutational load analyses indicated an increased proportion of homozygous-derived deleterious variants (i.e., drift load) among nonmigrant and island populations compared to those that are migrant or reside on the mainland, no significant differences in the proportion of heterozygous deleterious variants (i.e., inbreeding load) was observed. Our results provide evidence that high levels of inbreeding may not be an existential threat for some populations or taxa. Additional factors such as the timing and severity of population declines are important to consider in management decisions about extinction potential.
摘要：
为了防止灭绝，资源管理者的任务往往是增加一个群体的遗传多样性的关注，以防止近亲繁殖抑郁症或提高适应潜力在不断变化的环境。所有小种群都需要采取措施来增加其遗传多样性的假设可能是没有根据的，有限的保护资源可能会在其他地方得到更好的利用。我们在一个案例研究中测试了这一假设，该案例研究的重点是游猎鹰（Falcoperegrinus），一种世界性的环极物种，有19个命名亚种。我们使用全基因组重测序从所有游eg猎鹰亚种的多个个体中产生超过200万个单核苷酸多态性（SNP）。我们的分析揭示了亚种之间的广泛差异，许多岛屿限制和非迁徙种群的总体基因组多样性较低，近交系数升高(FROH)-在报告的最高水平中，与大陆和迁徙人群相比，纯合性（ROH）广泛。同样，大多数非迁徙或仅限于岛屿的亚种显示出更长的低有效种群规模（Ne）历史。虽然突变负荷分析表明纯合衍生的有害变体比例增加(即，漂移负荷)在非移民和岛屿人口中，与移民或居住在大陆的人口相比，杂合有害变体的比例没有显着差异(即，近交负荷)。我们的结果提供了证据，表明高水平的近亲繁殖可能不会对某些种群或分类群构成生存威胁。在有关灭绝潜力的管理决策中，必须考虑其他因素，例如人口下降的时间和严重程度。
