Understanding lifelong and multigenerational inbreeding effects in the Seychelles warbler

近交衰退需要在自然种群中测量，环境压力暴露了其有害影响，然而，这些研究可能大大低估了近交衰退，因为准确性受到诸如分散，不准确的亲子鉴定或量化近交问题等因素的影响。重要的是，他们通常只关注近亲繁殖个体的生存或繁殖（而不是近亲繁殖事件）-通常在他们生命的有限时期-因此错过了影响健康的关键因素，如产前不活力，交配成功或跨代效应。为了涵盖这些影响，应评估一个人在几代人中对群体的遗传贡献。研究也很少考虑波动的环境压力或地图年龄依赖性的影响。小塞舌尔莺种群库桑是一个很好的系统，在其中研究近亲繁殖的衰退。自1993年以来，几乎所有人都受到终生监测。没有迁移发生，所以扩散不会混淆生存估计。所有的繁殖都受到监控和分子验证，并且存在跨越>12代的>2000个个体的谱系。个体差异很大，他们是如何近亲繁殖，有限的评估表明，近亲繁殖的抑郁症occurs.MethodsFieldwork将被用来进一步加强个人为基础的生存和衰老数据集，了解系统，获得实地工作技能和联络国内保护利益相关者。学生将使用1600个个体的基因组重测序信息来计算全基因组纯合性（一个个体是如何近交的）。基于基因组的方法比使用基于谱系的估计更准确，并且还允许基于社会和遗传伙伴之间的基因组相似性来识别近亲繁殖事件。个体数据库将允许学生计算一生的生殖成功，确定差异生存和生殖成功如何对此做出贡献，以及女性和男性是否有所不同。他们还可以确定近亲繁殖是否会影响衰老的个体差异，这是许多物种中的一个重要现象。系谱将用于评估近亲繁殖如何影响个体对多代群体的贡献。最后，确定系谱中过去的近亲繁殖如何影响随后的近亲繁殖事件的影响，可以测试持续的近亲繁殖是否会导致净化和减少近亲繁殖衰退。将使用分层贝叶斯模型来分离因素的影响，即近交、近交亲本如何、近交事件、环境变异控制，并允许评估年龄和性别影响。

Inbreeding depression needs to be measured in natural populations where environmental stresses exposes its detrimental effects However, such studies probably greatly underestimate inbreeding depression because accuracy is undermined by factors such as dispersal, inaccurate parentage assignment or problems quantifying inbreeding. Importantly, they also normally only focus on the survival or reproduction of inbred individuals (and not inbreeding events)- often over limited periods of their lives - thus missing key components that impact fitness such as prenatal inviability, mating success or transgenerational effects. To encompass these effects an individual's genetic contribution to the population over generations should be assessed. Studies also rarely account for fluctuating environmental stresses1 or map age-dependent effects.The small Seychelles warbler population on Cousin is an excellent system in which to study inbreeding depression. Since 1993 nearly all individuals have been monitored throughout their lives. No migration occurs, so dispersal does not confound survival estimates. All reproduction is monitored and molecularly verified, and a pedigree of >2000 individuals spanning >12 generations exists. Individuals differ greatly in how inbred they are, and limited assessments indicate that inbreeding depression occurs.MethodsFieldwork will be used to further strengthen the individual-based survival and senescence dataset, understand the system, gain fieldwork skills and liaise with in-country conservation stakeholders. The student will use genomic resequencing information already available on 1600 individuals to calculate genome-wide homozygosity (how inbred an individual is). A genome-based approach is more accurate than using pedigree-based estimates and also allows inbreeding events to be identified based on genomic similarity between both social and genetic partners. The database on individuals will allow the student to calculate life-time reproductive success, determine how differential survival and reproductive success contribute to this, and whether that differs for females and males. They can also determine if inbreeding influences among-individual variation in senescence, an important phenomenon in many species. The pedigree will be used to assess how inbreeding affects an individual's contribution to the population over multiple generations. Finally, determining how past inbreeding in the pedigree affects the impact of subsequent inbreeding events can test whether sustained inbreeding can lead to purging and reduced inbreeding depression. Hierarchical Bayesian models will be used to separate the effects of factors i.e. being inbred, how inbred parents are, inbreeding events, control for environmental variation, and allow assessment of age and sex effects.