U. S. Geological Survey, Fort Collins Science Center, Fort Collins, Colorado, United States of America.
School of Environment, Resources and Sustainability, University of Waterloo, Waterloo, Ontario, Canada.
PLoS One. 2022 Sep 13;17(9):e0274189. doi: 10.1371/journal.pone.0274189. eCollection 2022.
Characterizing genetic structure across a species' range is relevant for management and conservation as it can be used to define population boundaries and quantify connectivity. Wide-ranging species residing in continuously distributed habitat pose substantial challenges for the characterization of genetic structure as many analytical methods used are less effective when isolation by distance is an underlying biological pattern. Here, we illustrate strategies for overcoming these challenges using a species of significant conservation concern, the Greater Sage-grouse (Centrocercus urophasianus), providing a new method to identify centers of genetic differentiation and combining multiple methods to help inform management and conservation strategies for this and other such species. Our objectives were to (1) describe large-scale patterns of population genetic structure and gene flow and (2) to characterize genetic subpopulation centers across the range of Greater Sage-grouse. Samples from 2,134 individuals were genotyped at 15 microsatellite loci. Using standard STRUCTURE and spatial principal components analyses, we found evidence for four or six areas of large-scale genetic differentiation and, following our novel method, 12 subpopulation centers of differentiation. Gene flow was greater, and differentiation reduced in areas of contiguous habitat (eastern Montana, most of Wyoming, much of Oregon, Nevada, and parts of Idaho). As expected, areas of fragmented habitat such as in Utah (with 6 subpopulation centers) exhibited the greatest genetic differentiation and lowest effective migration. The subpopulation centers defined here could be monitored to maintain genetic diversity and connectivity with other subpopulation centers. Many areas outside subpopulation centers are contact zones where different genetic groups converge and could be priorities for maintaining overall connectivity. Our novel method and process of leveraging multiple different analyses to find common genetic patterns provides a path forward to characterizing genetic structure in wide-ranging, continuously distributed species.
描述物种分布范围内的种群遗传结构对于管理和保护具有重要意义，因为它可以用于定义种群边界并量化连通性。广泛分布的物种居住在连续分布的栖息地中，对遗传结构的特征描述提出了巨大的挑战，因为许多使用的分析方法在距离隔离是潜在的生物模式时效果较差。在这里，我们使用一个具有重要保护意义的物种——大角羊（Centrocercus urophasianus）来说明克服这些挑战的策略，提供了一种识别遗传分化中心的新方法，并结合多种方法，为这种物种和其他类似物种提供管理和保护策略的信息。我们的目标是：（1）描述种群遗传结构和基因流动的大规模模式；（2）描述大角羊分布范围内的遗传亚种群中心。从 2134 个个体中提取样本，在 15 个微卫星基因座上进行基因分型。使用标准的 STRUCTURE 和空间主成分分析，我们发现了四个或六个大规模遗传分化区域的证据，以及我们的新方法确定的 12 个遗传分化亚种群中心。在连续栖息地（蒙大拿州东部、怀俄明州大部分地区、俄勒冈州大部分地区、内华达州和爱达荷州部分地区），基因流动更大，分化程度降低。正如预期的那样，在犹他州等栖息地碎片化的地区（有 6 个亚种群中心），遗传分化最大，有效迁移率最低。这里定义的亚种群中心可以进行监测，以保持遗传多样性和与其他亚种群中心的连通性。许多亚种群中心之外的区域是不同遗传群体汇聚的接触区，可能是维持整体连通性的优先区域。我们的新方法和利用多种不同分析方法寻找共同遗传模式的过程为广泛分布、连续分布的物种的遗传结构特征描述提供了一条前进的道路。
