Transmission Conflict in X - Y Chromosomes and Consequences to Heritable Variation in Fitness in Diopsid Dipterans

双翅目 X - Y 染色体的传输冲突及其适应性遗传变异的后果

• 批准号: 9807937
• 负责人: Gerald Wilkinson
• 金额: $ 6.5万
• 依托单位: University of Maryland, College Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-10-01 至 2000-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9807937&HistoricalAwards=false
• 关键词: Transmission; Conflict; Chromosomes; Consequences; Heritable

9807937 Wilkinson The evolutionary significance of sexual selection has received considerable study in the past twenty years, but controversy remains over the form and magnitude of benefits inherited by offspring as a consequence of mate choice. The work proposed in this study is designed to determine if transmission conflict between the sex chromosomes, i.e. sex-linked meiotic drive, can provide heritable variation in fitness that could be exploited by female choice. The motivation for this novel hypothesis is threefold. First, sex-linked meiotic drive influences fitness because it distorts the sex ratio. If females choose males possessing modifying genes that suppress sex-linked drive, then they will produce more offspring of the limiting sex. Sex-linked drive should be more common than autosomal drive because genetic exchange between the sex chromosomes is reduced or absent. The second motivation comes from theoretical work on the maintenance of genetic variation among Y chromosomes in general and X-linked meiotic drive in particular. This work indicates that heritable variation can be maintained either by recurrent sequential evolution of driving and suppressing alleles, a balanced polymorphism, or cyclical changes in allele frequencies. Recent work on several fly species indicates that drive-modifying genes are common and evolve rapidly. Third, theory and experimental work indicate that traits which benefit males but cost females should accumulate on the sex chromosomes. Direct evidence for an association between meiotic drive suppression and a sexually selected ornament was recently obtained in the lab. In two dramatically sexually dimorphic southeast Asian species of stalk-eyed flies (Diopsidae) long eye span was both preferred by females and indicated the presence of a Y-linked factor that suppresses X-linked meiotic drive. The work proposed here will determine how sex chromosome drive is maintained in stalk-eyed flies and, therefore, how this drive could influence the evolution of a male ornament. The extent to which X-linked drive and Y-linked suppression influence male and female fitness will be quantified in two ways. Replicate captive populations will be used to follow experimental evolution of driver and suppressor chromosome frequencies, sex ratio, and eye stalk length caused by selection. The life history components responsible for evolutionary change will be identified in a series of experiments that will involve testing each male and female genotype to determine if they differ in mating success, longevity, fertility, sperm competitive ability, or fecundity. Results from this work have the potential to influence current thinking on sexual selection. If the evidence is consistent with sex chromosome conflict influencing male eye span evolution, then the possibility that meiotic drive has influenced sexual selection in other species must be considered. This includes species known to exhibit meiotic drive, such as guppies, as well as species currently not known to exhibit meiotic drive, since one outcome of drive-suppressor coevolution is a temporary absence of detectable chromosome drive within a population.

小行星9807937 在过去的20年里，性选择的进化意义已经得到了大量的研究，但是关于配偶选择的结果给后代带来的好处的形式和数量仍然存在争议。 这项研究中提出的工作旨在确定性染色体之间的传递冲突，即性连锁减数分裂驱动，是否可以提供可遗传的适应性变化，可以被女性选择利用。 这个新假说的动机有三个方面。 首先，性连锁减数分裂驱动力影响健身，因为它扭曲了性别比例。 如果雌性选择拥有抑制性连锁驱动的修改基因的雄性，那么它们将产生更多的限制性别的后代。性连锁驱力应该比常染色体驱力更常见，因为性染色体之间的遗传交换减少或不存在。第二个动机来自理论工作的维持遗传变异之间的Y染色体一般和X连锁减数分裂驱动特别。这项工作表明，可遗传的变异可以保持驱动和抑制等位基因，平衡的多态性，或等位基因频率的周期性变化的周期性顺序进化。 最近对几种苍蝇的研究表明，驱动修饰基因是常见的，并且进化迅速。 第三，理论和实验工作表明，有利于男性但不利于女性的特征应该在性染色体上积累。 最近在实验室中获得了减数分裂驱动抑制和性选择装饰之间联系的直接证据。 在两个戏剧性的性二形东南亚物种的茎眼苍蝇（Diopsidae）长眼跨度都是女性的首选，并表示存在一个Y-连锁的因素，抑制X-连锁减数分裂驱动器。 这里提出的工作将确定性染色体驱动器是如何保持在茎眼苍蝇，因此，这种驱动器如何影响男性装饰品的进化。 X连锁驱动和Y连锁抑制影响男性和女性健康的程度将以两种方式量化。 复制圈养种群将被用来遵循实验进化的驱动和抑制染色体频率，性别比，和眼柄长度所造成的选择。 负责进化变化的生活史组成部分将在一系列实验中确定，这些实验将涉及测试每个男性和女性基因型，以确定它们在交配成功率，寿命，生育力，精子竞争能力或繁殖力方面是否存在差异。这项工作的结果有可能影响目前对性选择的思考。 如果证据是一致的性染色体冲突影响男性眼跨度的演变，那么减数分裂驱动的可能性，影响性选择在其他物种必须考虑。 这包括已知表现出减数分裂驱动的物种，如孔雀鱼，以及目前不知道表现出减数分裂驱动的物种，因为驱动-抑制共同进化的一个结果是在种群内暂时缺乏可检测的染色体驱动。