Department of Ecology, Evolution, and Natural Resources, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA.
New York State Department of Environmental Conservation, Albany, NY, USA.
Mol Ecol. 2021 Nov;30(22):5643-5657. doi: 10.1111/mec.15813. Epub 2021 Feb 8.
Rapid evolution of advantageous traits following abrupt environmental change can help populations recover from demographic decline. However, for many introduced diseases affecting longer-lived, slower reproducing hosts, mortality is likely to outpace the acquisition of adaptive de novo mutations. Adaptive alleles must therefore be selected from standing genetic variation, a process that leaves few detectable genomic signatures. Here, we present whole genome evidence for selection in bat populations that are recovering from white-nose syndrome (WNS). We collected samples both during and after a WNS-induced mass mortality event in two little brown bat populations that are beginning to show signs of recovery and found signatures of soft sweeps from standing genetic variation at multiple loci throughout the genome. We identified one locus putatively under selection in a gene associated with the immune system. Multiple loci putatively under selection were located within genes previously linked to host response to WNS as well as to changes in metabolism during hibernation. Results from two additional populations suggested that loci under selection may differ somewhat among populations. Through these findings, we suggest that WNS-induced selection may contribute to genetic resistance in this slowly reproducing species threatened with extinction.
环境的突然变化会促使有利性状快速进化，从而帮助种群从数量下降中恢复。然而，对于许多影响寿命较长、繁殖速度较慢的宿主的引入性疾病来说，死亡率很可能超过适应性新突变的获得。因此，适应性等位基因必须从现有遗传变异中选择，这一过程几乎不会留下可检测的基因组特征。在这里，我们提出了在白鼻综合征（WNS）中恢复的蝙蝠种群中选择的全基因组证据。我们在两个正在开始出现恢复迹象的小褐蝙蝠种群中，在 WNS 诱导的大量死亡事件期间和之后收集了样本，并在整个基因组的多个基因座上发现了来自现有遗传变异的软选择的特征。我们在一个与免疫系统相关的基因中鉴定出一个可能受到选择的基因座。多个疑似选择的基因座位于先前与宿主对 WNS 的反应以及冬眠期间代谢变化相关的基因内。来自另外两个种群的结果表明，选择的基因座在种群之间可能略有不同。通过这些发现，我们认为 WNS 诱导的选择可能有助于这种繁殖缓慢、濒临灭绝的物种产生遗传抗性。
