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.

9807937威尔金森性选择的进化意义在过去的二十年中已经获得了相当大的研究，但由于选择伴侣的选择而导致后代继承的福利的形式和幅度仍然存在。 这项研究中提出的工作旨在确定性染色体之间的传播冲突，即与性别链接的减数分裂驱动，可以提供可遗传的健身变化，而女性选择可以利用这一差异。 这个新假设的动机是三倍。 首先，性别链接的减数分裂驱动会影响健身，因为它会扭曲性别比。 如果女性选择具有抑制与性相关驱动力的基因的男性，那么她们将产生更多的限制性后代。性驱动器应该比常染色体驱动更为普遍，因为性别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上关于维持Y染色体之间遗传变异的理论工作，尤其是X连接的减数分裂驱动。这项工作表明，可以通过驱动和抑制等位基因，平衡的多态性或等位基因频率周期性变化的循环顺序演变来维持可遗传的变化。 关于几种飞蝇物种的最新工作表明，驱动器改良基因很常见并迅速发展。 第三，理论和实验工作表明，有益于男性但成本女性的特征应在性染色体上积累。 最近在实验室中获得了减数分裂驱动抑制与性选择的装饰之间关联的直接证据。 在两种巨大的性二态性二态东亚物种中，雌性既受到了眼睛的苍蝇（Diopsidae）的长眼跨度，并且表明存在抑制X连接减数分裂驱动的Y连锁因子。 这里提出的工作将决定如何在茎眼中保持性染色体驱动，因此，这种驱动器如何影响男性装饰品的演变。 X连锁驱动器和Y连锁抑制影响男性和女性健身的程度将通过两种方式进行量化。 重复圈养的种群将用于遵循驱动器和抑制染色体频率，性别比以及由选择引起的眼影长度的实验演变。 一系列实验将确定负责进化变化的生活史成分，该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，长寿，生育能力，精子竞争能力或繁殖力方面是否有所不同。这项工作的结果有可能影响当前对性选择的思维。 如果证据与影响男性眼镜的演变的性染色体冲突一致，那么必须考虑减数分裂驱动器影响其他物种的性选择的可能性。 这包括已知具有减数分裂驱动的物种，例如孔雀鱼，以及目前尚不清楚表现出减数分裂驱动的物种，因为驱动器抑制剂协同进化的一个结果是暂时没有人群中可检测到的染色体驱动。