Doctoral Dissertation Improvement: The Impact of Genetic Health on Parasite Prevalence, Diversity, and Burden in Wild Ring-Tailed Lemurs, Lemur catta

在脊椎动物中，遗传多样性影响个体健康的许多因素，如健康、生存和繁殖。与遗传多样性较低的近亲繁殖个体相比，遗传多样性较低的近亲繁殖个体寄生虫量更大，存活率降低，存活后代更少--这一现象被称为近亲繁殖衰退。除了这些个体成本，近亲繁殖衰退对种群和物种也有负面影响；因此，了解遗传多样性如何影响适合度对于保护濒危物种具有重要意义。灵长类动物特别容易受到近亲繁殖衰退的影响，因为它们的寿命长，繁殖率低，但到目前为止，还没有研究调查遗传多样性的丧失如何影响野生灵长类种群的健康、生存和繁殖。目前的挑战仍然是确定哪些特定的基因可以作为“遗传质量”的估计，因为它们会影响个体健康、生存和生殖方面的差异。一个可能导致个体差异的蛋白质编码区是主要组织相容性复合体(MHC)。这个基因家族控制着免疫系统识别细菌、病毒和寄生虫的能力，因此，对一个人及其后代的生存起着至关重要的作用。为了研究MHC如何影响受到威胁的灵长类动物的健康，环尾狐猴(Lemur Catta)，博士生凯瑟琳·格罗根(Duke University)在Christine Drea博士的指导下，将在马达加斯加Beza Mahavaly特别保护区的野生种群中，将MHC多样性与生存、繁殖成功和健康进行比较。使用长期人口普查数据衡量的生存和生殖成功，以及以寄生虫流行率、多样性和粪便样本中的负担衡量的健康将与MHC多样性进行比较。通过研究野生环尾狐猴的遗传多样性和适应性之间的关系，这项研究测试了MHC多样性的个体差异如何影响个体的健康、生存和繁殖。该奖项将用于资助一名研究生的培养。此外，遗传信息将为保护工作提供信息。

In vertebrates, genetic diversity influences many elements of an individual's fitness, such as health, survival, and reproduction. 'Inbred' individuals with less genetic diversity have greater parasite loads, reduced survivorship, and produce fewer surviving offspring than do more genetically diverse, or 'outbred" individuals - a phenomenon called inbreeding depression. Beyond these individual costs, inbreeding depression also has negative consequences on populations and species; therefore, understanding how genetic diversity impacts fitness has significant implications for conserving endangered species. Primates are especially vulnerable to inbreeding depression because of their long lifespans and low reproduction rates, yet thus far, no study has investigated how the loss of genetic diversity affects the health, survival, and reproduction of a wild primate population. The challenge remains to identify the specific genes that can serve as estimates of 'genetic quality' because they influence variation in individual health, survival, and reproduction. One protein-coding region likely to contribute to individual differences is the Major Histocompatibility Complex (MHC). This family of genes controls the immune system's ability to recognize bacteria, viruses, and parasites, and thus, plays an essential role in the survival of an individual and their offspring. To examine how MHC impacts fitness in a threatened primate, the ring-tailed lemur (Lemur catta), doctoral student Kathleen Grogan (Duke University), under the supervision of Dr. Christine Drea, will compare MHC diversity against survival, reproductive success, and health across an environmental stressor in a wild population at Beza Mahafaly Special Reserve, Madagascar. Survival and reproductive success, measured using long-term census data, and health, measured as parasite prevalence, diversity, and burden in fecal samples collected (a) under 'typical' environmental conditions and (b) following a severe drought, will be compared against MHC diversity. By examining the relationship between genetic diversity and fitness in wild ring-tailed lemurs, this research tests how individual differences in MHC diversity influence that individual's health, survival, and reproduction. This award will support the training of a graduate student. Additionally, the genetic information will inform conservation efforts.