Advancing a genealogical and systems-based theory of the evolution of biodiversity

自然界的多样性是多元的。 个体在多于一个表型性状上彼此不同，其中表型性状仅仅是个体的测量的身体和/或行为属性。 个体和物种在多元表型上的差异部分地决定了它们所占据的生态位的差异。 多元生态位的概念可以追溯到哈钦森1957年的一篇经典论文。 例如，植物物种的授粉生态位是其开花时间、花的颜色、花的对称性、花蜜产量、花粉产量和花的数量的函数。 一个物种的多元生态位的演变取决于几个因素，包括该物种所占据区域的物理属性、与之相互作用的其他物种以及组成该物种的个体的基因型。 此外，有证据表明，生态系统进程部分取决于组成群落的物种的多元表型。使用理论建模，我的实验室研究物种的进化历史如何影响其多元多样性。 我们知道，从以前的工作，家谱的历史可以限制多元多样性，但机制，可以克服这一限制还没有完全理解。 我实验室目前的工作是探索可以克服这种限制的遗传机制，重点是上位基因作用。 当突变相互作用以非加性方式产生表型时，就会发生上位性基因作用。 我的实验室最近研究无性种群的工作表明，上位基因作用减少了系谱结构对多元进化的约束。在这份资助申请中，我们寻求支持来描述上位性基因作用如何影响经历有性生殖和重组的群体的多元多样性。 此外，我们试图确定多倍体物种减数分裂过程的独特方面是否促进了多元多样性的进化。最近的理论工作表明，生态多样化是更容易当它涉及到一个多变量与单变量性状。 在这里，我们试图确定上位性是否可以进一步促进生态多样性，这对于理解物种形成的原因可能很重要。用系谱学方法来模拟上位性和多变量性状进化在技术上是复杂的。 因此，在自然环境中很难直接估计模型中的参数。 在这项研究中，我们试图开发一种间接的方法来估计我们模型的属性，以测试上位基因作用与系谱结构的结合是否真的对确定自然界的多样性很重要。最后，我们试图解决多元多样性首先是如何产生的问题。 发育生物学的研究表明，模块化基因作用和基因复制可能促进了多样性的进化。 最近的实证研究表明，基因复制引入了新的上位相互作用。 在这里，我们试图确定是否基因重复与上位基因作用相结合，促进了多元多样性的演变。

Diversity in nature is multivariate. Individuals differ from each other in more than one phenotypic trait, where a phenotypic trait is simply a measured physical and/or behavioural attribute of an individual. Differences among individuals and species in their multivariate phenotype determine, in part, differences in the niche they occupy. This idea of a multivariate niche traces back to a classic paper by Hutchinson in 1957. For example the pollination niche of a plant species is a function of its flowering time, flower color, flower symmetry, nectar production, pollen production, and flower number. The evolution of a species' multivariate niche depends on several factors, including the physical attributes of the area the species occupies, the other species it interacts with and the genotypes of individuals that make up the species. Furthermore, there is evidence that ecosystem processes are determined, in part, by the multivariate phenotypes of species that compose a community.**Using theoretical modeling, my lab studies how the evolutionary history of a species affects its multivariate diversity. We know from previous work that genealogical history can restrict multivariate diversity, but the mechanisms that can overcome this limit are not fully understood. Current work in my lab is exploring genetic mechanisms that can overcome this constraint, with a focus on epistatic gene-action. Epistatic gene-action occurs when mutations interact to produce a phenotype in a non-additive manner. Recent work in my lab studying asexual populations showed that epistatic gene-action reduces the constraint of genealogical structure on multivariate evolution.**In this grant application we seek support to characterize how epistatic gene-action affects multivariate diversity in populations that undergo sexual reproduction and recombination. In addition, we seek to determine whether unique aspects of the meiotic process in polyploid species facilitate the evolution of multivariate diversity.**Recent theoretical work indicates that ecological diversification is easier when it involves a multivariate versus a univariate trait. Here we seek to determine whether epistasis can further facilitate ecological diversification, which may be important for understanding the causes of speciation.**The genealogical approach to modeling epistasis and multivariate trait evolution is technically complicated. As such, direct estimation of parameters in the model is difficult in natural settings. In this grant we seek to develop an indirect approach to estimate attributes of our model that would test whether epistatic gene-action in combination with genealogical structure is, in fact, important with respect to determining diversity in nature.**Lastly, we seek to address the question of how multivariate diversity arises in the first place. Work in developmental biology indicates modular gene-action and gene duplication may facilitate the evolution of diversity. Recent empirical work suggests that gene duplications introduce new epistatic interactions. Here we seek to determine whether gene duplication in combination with epistatic gene-action facilitates the evolution of multivariate diversity.