Drift, selection and adaptive variation in small populations of a threatened rattlesnake
Drift, selection and adaptive variation in small populations of a threatened rattlesnake
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受威胁响尾蛇小种群的漂移、选择和适应性变异
DOI：
10.1111/mec.15517
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发表时间：
2020
影响因子：
4.9
通讯作者：
Gibbs, H. Lisle
中科院分区：
文献类型：
--
作者：
Ochoa, Alexander;Broe, Michael;Moriarty Lemmon, Emily;Lemmon, Alan R.;Rokyta, Darin R.;Gibbs, H. Lisle
保护遗传学的一个重要目标是确定小种群的生存能力是否会因遗传漂变而丧失适应性变异而降低。在这里，我们评估的影响漂移和选择的直接措施的适应性变化（毒素位点编码毒液蛋白）在东部massasauga响尾蛇（Sistrurus catenatus），一种受威胁的爬行动物，存在于小的孤立的人群。我们估计了该物种12个种群中46个毒素基因座和1,467个对照基因座的个体多态性水平，并将结果与链鞭金藻及其最近亲属西方马萨索加（S. tergeminus）物种形成后相同基因座上的选择模式进行了比较。多线的证据表明，漂移和选择有可观察到的影响常设适应性变化。为了支持漂移效应，我们几乎没有发现种群内毒素变异的选择证据，并且当前适应性变异水平与有效种群大小的长期和短期估计值之间存在显着的正相关关系。然而，我们还观察到种群中毒素基因座的定向选择水平与种间选择分析预测的模式大致相似，这些分析早于最近的漂移效应，尽管短期有效大小很小，但这些基因座的功能变异仍然存在。这表明，种群中存在的许多适应性变异可能代表了“漂移债”的一个例子，这是一种非平衡状态，在这种状态下，当前的变异水平高估了未来种群中存在的功能遗传多样性的数量。
An important goal of conservation genetics is to determine if the viability of small populations is reduced by a loss of adaptive variation due to genetic drift. Here, we assessed the impact of drift and selection on direct measures of adaptive variation (toxin loci encoding venom proteins) in the eastern massasauga rattlesnake (Sistrurus catenatus), a threatened reptile that exists in small isolated populations. We estimated levels of individual polymorphism in 46 toxin loci and 1,467 control loci across 12 populations of this species, and compared the results with patterns of selection on the same loci following speciation ofS. catenatusand its closest relative, the western massasauga (S. tergeminus). Multiple lines of evidence suggest that both drift and selection have had observable impacts on standing adaptive variation. In support of drift effects, we found little evidence for selection on toxin variation within populations and a significant positive relationship between current levels of adaptive variation and long‐ and short‐term estimates of effective population size. However, we also observed levels of directional selection on toxin loci among populations that are broadly similar to patterns predicted from interspecific selection analyses that pre‐date the effects of recent drift, and that functional variation in these loci persists despite small short‐term effective sizes. This suggests that much of the adaptive variation present in populations may represent an example of “drift debt,” a nonequilibrium state where present‐day levels of variation overestimate the amount of functional genetic diversity present in future populations.
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影响因子：
4.9
作者：
Timothy J. Thurman;R. Barrett
通讯作者：
Timothy J. Thurman;R. Barrett
影响因子：
7.7
作者：
Excoffier, Laurent;Lischer, Heidi E. L.
通讯作者：
Lischer, Heidi E. L.
比较毒腺的比较转录组调查（Viperidae：echis）显示了家族内基因多样性和新型毒液转录本。
影响因子：
4.4
作者：
Casewell NR;Harrison RA;Wüster W;Wagstaff SC
通讯作者：
Wagstaff SC
影响因子：
56.9
作者：
Jones, Matthew R.;Mills, L. Scott;Good, Jeffrey M.
通讯作者：
Good, Jeffrey M.
通过隔离和历史杂交发现受威胁爬行动物的神秘谱系的起源
影响因子：
3.8
作者：
MG Sovic;AC Fries;HL Gibbs
通讯作者：
HL Gibbs