The Evolutionary Dynamics of Genetic Conflict: the Origin, Maintenance and Loss of Paternal Genome Elimination.

生命之树上的繁殖：为什么有这么多方式？在有性繁殖过程中，两个不相关的个体合作实现一个共同的目标：将自己的基因传递给下一代。然而，这种合作并不是没有冲突，父母可以为谁抚养孩子而争吵，伴侣可以欺骗和与其他伴侣交配。尽管存在这些冲突，但至少在大多数动物中，父母的基因在后代中的代表是平等的。然而，情况并不总是如此。在我的研究中，我研究了一组昆虫，它们的繁殖能力差异非常大，而且进化创新似乎降低了雄性的重要性。例如，在柑橘粉虱(一种植物寄生虫)和人体虱子(我们自己的寄生虫)中，仍然需要雄性来使雌性受精，但雌性可以从她的儿子身上消除他的基因。这种不寻常的生殖方式被称为“父系基因组消除”(PGE)，这符合雌性的利益，因为她的儿子总是会遗传她的基因，而不是她伴侣的基因。我用这两个物种来研究两性之间的冲突如何导致这种奇怪的生殖行为的进化。我的目标是通过使用一系列最先进的基因技术，研究他们的后代基因的行为，来了解男性和女性是如何竞争的。在粉虱身上，我们知道父亲的基因不仅从其儿子的精子中被消除，而且还被阻止表达。我的目标是研究粉虱和虱子的雄性父亲基因的表达，以了解这些基因是否有机会对抗它们的消除。父亲的基因从儿子身上消除的方式仍然不清楚，尽管这似乎发生在精子产生的同时，发生在睾丸中。我的目标是通过比较有无前列腺素E的男性的精子产生过程来研究虱子的消除机制。进化生物学中的一些最优秀的思想家已经对前列腺素E的进化进行了理论分析，但到目前为止，这些理论都没有得到实证检验。在这里，我将使用人体虱子，其中前列腺素E是最近才被发现来测试这些理论。我将使用患有和不患有前列腺素E的个体之间的杂交来研究这种特征是如何遗传的，以及它如何在种群中传播。在大多数患有前列腺素E的物种中，似乎母亲的基因获胜了，并确保了他们的儿子将把这些基因遗传给他的孩子。然而，情况可能并不总是如此。在这项提案的最后一个项目中，我将研究一类澳大利亚昆虫，它们与粉虱密切相关。先前的研究表明，一些物种已经失去了前列腺素E，可能已经恢复了“正常”的繁殖。我将研究这一分支中的物种，看看前列腺素E丢失的频率以及哪些因素可能是原因。这些方法加在一起，将解决导致不寻常生殖系统进化的力量。这些知识将帮助科学家理解为什么生殖这个如此基本的过程在生命中如此不同。

Reproduction across the tree of life: Why so many ways of doing it?During sexual reproduction, two unrelated individuals cooperate to achieve a common goal: pass on their genes to the next generation. This cooperation is however not without conflict, parents can fight over who raises the kids, and partners can cheat and mate with other mates. Despite these conflicts genes of the mother and father are, at least in most animals, equally represented in the offspring. This is, however, not always the case. In my research I study a group of insects whose reproduction is incredibly variable and where evolutionary innovations appear to have reduced the importance of males. For example in the citrus mealybug (a plant parasite) and the human body lice (our own parasite), males are still needed to fertilize females, but the female can eliminate his genes from her son. This unusual type of reproduction called "Paternal Genome Elimination" (PGE) is in the female's interest as her sons will always pass on her genes, instead of those of her partner. I use these two species to study how conflict between the sexes can have lead to the evolution of this strange reproductive behaviour. I aim to understand how males and females compete by studying the behavior of their genes within their offspring, using a range of state-of-the-art genetic techniques. In mealybugs we know that a father's genes are not simply eliminated from its sons sperm, but also prevented from being expressed. I aim to study the expression of paternal genes in males of both mealybugs and lice to understand if these genes might have the opportunity to fight against their elimination.The way a father's genes are eliminated from his sons is still unclear, although it seems to take place in the testis while sperm is produced. I aim to study the mechanism of elimination in lice by comparing the process of sperm production in males with and without PGE. Some of the finest minds in evolutionary biology have theorized about the evolution of PGE, yet to date, none of these theories have been tested empirically. Here I will use the human body louse, in which PGE has only recently been discovered to test these theories. I will use crosses between individuals with and without PGE to study how this trait is inherited and how it can spread though the population.In most species with PGE it seems that the mother's genes have won and ensured that they are the ones their sons will pass on to his children. This might not always be the case though. In the final project of this proposal I will study a clade of Australian insect, closely related to mealybugs. Previous research suggests that some species have lost PGE and might have reverted back to "normal" reproduction. I will study species across this clade to see how often PGE has been lost and which factors might be responsible.Taken together, these approaches will address the forces responsible for the evolution of an unusual reproductive system. This knowledge will help scientists understand why reproduction, a process so fundamental, is so variable across life.