Understanding the strength and demographic consequences of inbreeding depression in the wild, and the subsequent implications for conservation

了解野外近交衰退的强度和人口统计后果，以及随后对保护的影响

• 批准号: RGPIN-2019-05064
• 负责人: Frasier, Timothy
• 金额: $ 2.04万
• 依托单位: Saint Mary's University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=682947
• 关键词: Understanding; strength; demographic; consequences; inbreeding

The negative fitness consequences associated with inbreeding, as well as their avoidance, represent some of the central factors shaping the biology of animal populations. These range from individual-based effects such as on behaviour and fitness, to population-wide effects such as on population growth rates and extinction probabilities. Inbreeding has therefore been a key topic of biological interest for over a century. Despite this long-term interest, our understanding of the strength and demographic consequences of inbreeding depression in the wild is still in its infancy. This situation results from two main constraints. First, much of our understanding still comes from studies of laboratory and captive populations, where conditions and selection pressures are relatively homogeneous and benign, resulting in underestimates of the effects of inbreeding depression. The second constraint is that, until recently, studies have had low power to quantify individual inbreeding coefficients with reasonable accuracy and precision. The main goal of the proposed work is to improve this understanding by overcoming these constraints through the combination of long-term individual-based field studies and high-density SNP genotypes to quantify the impacts of inbreeding on individual health, reproductive success, and survival in the endangered North Atlantic right whale (Eubalaena glacialis); and to assess how these individual effects combine to shape population growth rates and recovery potential. My approach will have five major components. The first will be to genotype individuals at tens of thousands of SNPs to provide dense marker panels required for estimating inbreeding coefficients with high precision and accuracy. For step 2 use these data to quantify the impact of inbreeding on reproductive performance. In step 3 we will quantify the impact of inbreeding on individual health and survival. For step 4 we will conduct individual-based population viability analyses to assess how the identified impacts of inbreeding on individual fitness scale-up to influence the recovery potential and viability of this species. Lastly, for step 5 we will conduct preliminary tests for “outlier loci” to see if one or more loci stand out as particularly strong drivers of these effects. This work will have substantial impacts at two different scales. At a narrow scale it will identify the degree to which inbreeding is shaping patterns of individual fitness, and how these individual effects combine to limit the recovery potential of this endangered species. At a broader scale, this work will provide much needed information on the strength and demographic consequences of inbreeding depression in the wild, the subsequent effects on recovery potential and population viability, and the implications for conservation.

与近亲繁殖相关的负面适应性后果及其回避代表了影响动物种群生物学的一些核心因素。这些范围从基于个人的影响（例如对行为和健康的影响）到整个人口的影响（例如对人口增长率和灭绝概率的影响）。因此，一个多世纪以来，近亲繁殖一直是生物学界关注的一个关键话题。尽管存在这种长期的兴趣，但我们对野外近交衰退的强度和人口统计后果的了解仍处于起步阶段。这种情况是由两个主要限制造成的。首先，我们的大部分理解仍然来自对实验室和圈养种群的研究，这些种群的条件和选择压力相对均匀且良性，导致低估了近交衰退的影响。第二个限制是，直到最近，研究以合理的准确度和精确度量化个体近交系数的能力较低。拟议工作的主要目标是通过结合长期的个体现场研究和高密度 SNP 基因型来克服这些限制，从而提高这种认识，以量化近亲繁殖对濒临灭绝的北大西洋露脊鲸 (Eubalaena glacialis) 个体健康、繁殖成功和生存的影响；并评估这些个体效应如何结合起来影响人口增长率和恢复潜力。我的方法有五个主要组成部分。第一个是对数万个 SNP 的个体进行基因分型，以提供高精度和准确度估计近交系数所需的密集标记组。对于步骤 2，使用这些数据来量化近亲繁殖对繁殖性能的影响。在第三步中，我们将量化近亲繁殖对个体健康和生存的影响。对于步骤 4，我们将进行基于个体的种群生存力分析，以评估已确定的近亲繁殖对个体适应度扩大的影响如何影响该物种的恢复潜力和生存能力。最后，对于第 5 步，我们将对“异常位点”进行初步测试，看看是否有一个或多个位点作为这些效应的特别强驱动因素而脱颖而出。这项工作将在两个不同层面产生重大影响。在小范围内，它将确定近亲繁殖在多大程度上塑造个体健康模式，以及这些个体效应如何结合起来限制这一濒危物种的恢复潜力。在更广泛的范围内，这项工作将提供急需的信息，包括野生近交衰退的强度和人口后果、对恢复潜力和种群活力的后续影响以及对保护的影响。