Department of Zoology, Stockholm University, Stockholm, Sweden.
Department of Bioinformatics and Genetics, Swedish Museum of Natural History, Stockholm, Sweden.
Mol Ecol. 2021 Jun;30(12):2790-2799. doi: 10.1111/mec.15943. Epub 2021 May 20.
Reduced fitness through genetic drift and inbreeding is a major threat to small and isolated populations. Although previous studies have generally used genetically verified pedigrees to document effects of inbreeding and gene flow, these often fail to capture the whole inbreeding history of the species. By assembling a draft arctic fox (Vulpes lagopus) genome and resequencing complete genomes of 23 additional foxes born before and after a well-documented immigration event in Scandinavia, we here look into the genomic consequences of inbreeding and genetic rescue. We found a difference in genome-wide diversity, with 18% higher heterozygosity and 81% lower F in immigrant F1 compared to native individuals. However, more distant descendants of immigrants (F2, F3) did not show the same pattern. We also found that foxes with lower inbreeding had higher probability to survive their first year of life. Our results demonstrate the important link between genetic variation and fitness as well as the transient nature of genetic rescue. Moreover, our results have implications in conservation biology as they demonstrate that inbreeding depression can effectively be detected in the wild by a genomic approach.
遗传漂变和近亲繁殖导致的适应能力下降是小型和隔离种群的主要威胁。尽管先前的研究通常使用经过基因验证的系谱来记录近亲繁殖和基因流动的影响，但这些研究往往无法捕捉到物种的整个近亲繁殖历史。通过组装北极狐（Vulpes lagopus）的基因组草图并对 23 只在斯堪的纳维亚半岛有记录的移民事件前后出生的狐狸进行全基因组重测序，我们研究了近亲繁殖和遗传拯救的基因组后果。我们发现了全基因组多样性的差异，与本地个体相比，移民 F1 的杂合度高出 18%，而 F 值则低 81%。然而，移民的更远代后代（F2、F3）则没有表现出相同的模式。我们还发现，近亲繁殖程度较低的狐狸有更高的概率在其生命的第一年存活下来。我们的研究结果表明遗传变异与适应能力之间存在重要联系，以及遗传拯救的短暂性。此外，我们的研究结果在保护生物学中具有意义，因为它们表明，通过基因组方法可以在野外有效地检测到近交衰退。
