Developing and Testing Evolutionary Models of Non-reproductive Sex including Homosexuality

同性恋行为通常被认为是一个“达尔文悖论”，因为关注非生殖性行为而损害生殖性行为会导致更少的后代。然而，同性之间的性行为（同性恋）在自然界中很常见，在人类和其他灵长类动物中尤其常见。已经提出了许多模型来解释同性恋的进化，从亲属选择到内部性冲突。虽然这些模型中的许多模型往往被视为彼此的替代品，但实际上它们之间存在很大程度的兼容性和预测的广泛重叠。这是由于，至少部分是由于最终和近似假设的合并，以及等价的不相称的参数，如选择模式，性状的适应性效应和遗传结构的类型，这些参数跟踪进化过程的不同部分。目前的博士项目的目的是双重的;（1）解决目前的理论文献中的不一致，以产生一个同性恋进化的一般框架，由理论群体遗传学模型支撑。(2)在经验数据集上测试该框架的预测，包括：将支持同性恋的多态性稳定性的单基因座遗传和表观遗传模型（如超显性模型）扩展到适合复杂性状结构的多基因座模型。这将是Savolainen和Hodgson提出的双性恋优势模型正式化过程的一部分。将亲属选择纳入同性恋的理论进化遗传模型，以便为何时可以将性行为作为亲属利他主义的一种形式进行推广提供强有力的预测。其目的是将生态参数纳入所有模型中，以改进不同社会背景（如交配系统）的预测。测试同性恋跨分类群分布的理论框架的预测，更具体地说，与Savolainen小组的其他成员合作，在圣地亚哥岛研究网站的行为数据集中进行研究。

Homosexual behaviour has often been considered a 'Darwinian paradox' because a focus on non-reproductive sexual behaviour to the detriment of reproductive sex should result in fewer offspring. Yet, sexual behaviour between members of the same sex (homosexuality) is commonly observed in nature, and is particularly frequent in humans and other primates. A number of models have been proposed to explain the evolution of homosexuality, ranging from kin selection to intralocus sexual conflict. While many of these models have often been framed as alternatives to each other, there is actually a large degree of compatibility between them and extensive overlap in predictions. This is due, at least in part, to the conflation of both ultimate and proximate hypotheses, and equivalating incommensurate parameters such as mode of selection, fitness effects of traits, and types of genetic architecture, which track different parts of the evolutionary process. The present PhD projects aims are twofold; (1) To resolve current inconsistencies in the theoretical literature to produce a general framework for the evolution of homosexuality, underpinned by theoretical population genetics models. (2) To test predictions arising from this framework on empirical datasets.This will include:Extending single loci genetic and epigenetic models for the stability of polymorphism underpinning homosexuality, such as overdominance models, to multilocus models appropriate for complex trait architecture. This will be part of the process of formalising the Bisexuality Advantage Model proposed by Savolainen & Hodgson.Incorporating kin selection in to theoretical evolutionary genetic models of homosexuality in order to provide robust predictions for when sexuality could be promoted as a form of kin altruism. The aim is to incorporate ecological parameters in to all models to refine predictions across different social contexts such as mating systems.Testing predictions from the theoretical framework in cross-taxa distributions of homosexuality, and more specifically in behavioural datasets from studies on the Cayo Santiago research site in collaboration with other members of the Savolainen group.