How do sex ratio distorting symbionts affect the evolution of their host?

性别比例扭曲的共生体如何影响宿主的进化？

基本信息

批准号：
NE/N010434/1
负责人：
Gregory Hurst
金额：
$ 58.39万
依托单位：
University of Liverpool
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2016
资助国家：
英国
起止时间：
2016 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FN010434%2F1
关键词：
How do sex ratio distorting

项目摘要

The biology of animals is in part a function of the microbes they interact with. During digestion, for instance, food is broken down both by enzymes secreted by our digestive system and those secreted by the microbes that live within the gut. In many insects, microbe-host interactions are even more developed. Bacterial symbionts live inside the cells of the insect body, and these are passed from a female to her offspring via her eggs: heritable symbiosis. We know a lot about how these symbionts affect the individual they infect. One particularly interesting impact is male-killing, where the bacterium passes from a female to her eggs, and kills those which develop as males. We know male-killing bacteria are common: they are present in many species, and, where they are present, can be present in the majority of individuals - this produces insect populations where males are rare. However, we know little about how these bacteria affect insect ecology or evolution. A variety of researchers believe these symbionts may drive changes in the way male and female insects are formed during development, sex determination. The hypothesis is simple - where symbionts target males only, natural selection counteracts this by favouring new ways of making a male that escape male-killing. This study will examine this theory for a recent case of evolution of the blue moon butterfly to avoid the action of male-killing bacterium called Wolbachia. We have documented the spread of a mutation that rescues male blue moon butterflies from Wolbachia-induced death. This project will establish what this mutation is, whether it involves changes in a gene called 'doublesex', which defines male and female characteristics in insects. A second aspect of male-killers is that they may drive very strong natural selection to rescue males. The intensity of selection is such that the changes that occur to rescue males may be otherwise deleterious. A second aim of the project is to establish if this is true, and whether the mutation (beyond rescuing males) degrades male and female function. In completing this project, we will present the first direct test of the theory that the processes that make males/females different can be driven by microbes. This is an enigmatic link that would make clear the interdependence of insect and microbe evolution.

动物的生物学部分是与它们相互作用的微生物的功能。例如，在消化过程中，食物会被消化系统分泌的酶和肠道内微生物分泌的酶分解。在许多昆虫中，微生物与宿主的相互作用甚至更加发达。细菌共生体生活在昆虫体内的细胞内，这些共生体通过雌性的卵从雌性传递给其后代：可遗传的共生。我们非常了解这些共生体如何影响它们感染的个体。一个特别有趣的影响是杀死雄性，即细菌从雌性传播到她的卵子，并杀死那些发育成雄性的卵。我们知道杀死雄性的细菌很常见：它们存在于许多物种中，并且，只要有它们存在，就可以存在于大多数个体中——这会产生雄性罕见的昆虫种群。然而，我们对这些细菌如何影响昆虫生态或进化知之甚少。许多研究人员认为，这些共生体可能会改变雄性和雌性昆虫在发育和性别决定过程中的形成方式。这个假设很简单——当共生体只针对雄性时，自然选择就会通过新的方式来抵消这种现象，从而使雄性免于被杀。这项研究将在最近的蓝月蝴蝶进化案例中检验这一理论，以避免被称为沃尔巴克氏体的雄性杀死细菌的作用。我们已经记录了一种突变的传播，该突变使雄性蓝月蝴蝶免于沃尔巴克氏体引起的死亡。该项目将确定这种突变是什么，是否涉及一种称为“双性”的基因的变化，该基因定义了昆虫的雄性和雌性特征。雄性杀手的第二个方面是，它们可能会驱动非常强大的自然选择来拯救雄性。选择的强度如此之大，以至于为拯救雄性而发生的变化可能是有害的。该项目的第二个目标是确定这是否属实，以及这种突变（除了拯救男性之外）是否会降低男性和女性的功能。在完成这个项目时，我们将首次对这一理论进行直接测试，即使男性/女性不同的过程可以由微生物驱动。这是一个神秘的联系，它将阐明昆虫和微生物进化的相互依赖性。