Evolutionary consequences of polyploidy and sexual system variation in mosses

许多植物、真菌和动物是单性的，有单独的雄性和雌性个体。然而，在这些群体中，许多物种都有雌雄同体的个体。什么样的条件有利于哪种策略？我的研究主要集中在苔藓上，以测试有关选择不同性策略的进化和维持的因素的问题。这是因为苔藓具有有利于实验的特性，例如许多苔藓的繁殖时间较短，以及在基因上操纵性别的成熟技术。此外，由于对性别的遗传控制非常不同，在苔藓中，组合性和分离性之间的进化变化的原因很可能是不同的，对苔藓的研究可以作为对动物和开花植物的理论工作的普遍性的检验。苔藓有单倍体性染色体：雌性有一个X，雄性有一个Y（与人类相反，男性是XY）。据预测，在苔藓中，基因组加倍会导致个体同时拥有X染色体和Y染色体，这可能是雌雄同体。我的研究将通过实验来检验这一雌雄同体的进化途径，并检验单性和雌雄同体在基因组加倍后的进化稳定性。这项研究的意义超出了苔藓。虽然X染色体和Y染色体有在不同性别中不能重组的区域，但重组现在可以在基因组复制后发生。这将允许X或Y染色体上的突变暴露于选择中。检查这种影响将使我们了解所有有性生物体中重组和基因突变之间的相互作用。

Many plants, fungi and animals are unisexual and have separate male and female individuals. Yet in each of these groups, many species have hermaphroditic individuals. What conditions favour which strategy? My research focusses on mosses to test questions about the factors selecting for the evolution and maintenance of different sexual strategies. This is because mosses have features that make them conducive to experimentation, such as a short time to reproduction in many, and established techniques to genetically manipulate the sexes. In addition, the cause of evolutionary changes between combined and separate sexes is likely to be different in mosses as the genetic control of sex is very different, and research in mosses can serve as a test of the generality of theoretical work developed for animals and flowering plants. Mosses have haploid sex chromosomes: females have one X and males one Y (contrast this with humans, where males are XY). Genome doubling in mosses is predicted to result in individuals with both X and Y chromosomes, which could be hermaphrodite. My research will experimentally test this proposed evolutionary pathway to hermaphroditism and examine the evolutionary stability of unisexuals and hermaphrodites following genome doubling. This research has implications that extend beyond mosses. While X and Y chromosomes have regions that do not recombine in separate sexes, recombination can now occur following genome duplication. This will allow mutations on the X or Y chromosomes to be exposed to selection. Examining the effect of this will allow us to understand the interplay between recombination and genetic mutations in all sexual organisms.