Selfish genetic elements and population viability: the impact of temperature and sexual selection

自私的遗传因素和种群生存能力：温度和性选择的影响

基本信息

批准号：
NE/F005245/1
负责人：
Gregory Hurst
金额：
$ 1.76万
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：
2008
资助国家：
英国
起止时间：
2008 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FF005245%2F1
关键词：
Selfish genetic elements population viability

项目摘要

Climate change is proceeding apace. Many populations are predicted to go extinct, unable to respond rapidly enough to their changing environment. We have little understanding about the extent to which populations have the ability to evolve in response to changing temperatures. Fly species have provided much needed information about potential adaptation to environmental changes in the wild. This is largely because some of their genes are contained in tightly linked groups (inversions) that are always inherited together and passed down as a unit through the generations. This allows quantification of changes in the frequencies of genes contained within these locked chromosomal regions in relation to changing environmental factors such as temperature. Any change in these genes can only be attributed to evolution. Many populations harbour selfish genetic elements (SGEs), genes that unfairly bias inheritance to increase their spread in a population. In spite of this transmission advantage, many SGEs are transient in natural population or found at lower than expected frequencies. It is not clear what factors regulate SGEs in the wild. We will examine the impact of temperature variation on the frequency of a selfish gene (present within an inversion) in a fruit fly that cause female biased population sex ratios, and hence may cause population extinction due to lack of males. The frequency of this sex ratio distorter has remained stable for >70 years in the Northwestern USA, but the underlying reason for the observed gradient among populations remains unknown. We will quantify changes in the frequency of the sex ratio distorting gene in natural populations across a temperature gradient. One possibility is that changes in female mating behaviour may directly regulate the frequency of sex ratio drive. We have found that female multiple mating can dramatically reduce the frequency of sex ratio distorting genes in lab populations. This is due to the poor sperm competitive ability of males carrying the sex ratio gene compared to non-carrying males. We will evaluate the importance of temperature in altering female mating frequencies in the wild and therefore the level of sperm competition encountered by males carrying the sex ratio gene. We predict that low temperatures are unfavourable to sex ratio males because females live longer and may mate more frequently at lower temperature and hence the level of sperm competition is greater, reducing the paternity of sex ratio males barring their spread. This research will provide valuable information about the ability of populations to adapt to changing environments. This may provide important information about which species may turn into potential agricultural pests and disease vectors, whereas other species risk going extinct. It will also be of value to captive breeding programmes and in biological control schemes by highlighting the link between female mating frequency and the spread of unfavourable/favourable genes.

气候变化正在迅速发生。由于无法对不断变化的环境做出足够迅速的反应，许多种群预计将灭绝。我们对种群响应温度变化而进化的能力知之甚少。蝇类提供了有关野外环境变化的潜在适应能力的急需信息。这主要是因为它们的一些基因包含在紧密相连的群体（倒位）中，这些群体总是一起遗传并作为一个单元代代相传。这允许量化这些锁定染色体区域内包含的基因频率的变化，这些变化与环境因素（例如温度）的变化有关。这些基因的任何变化都只能归因于进化。许多人群都含有自私遗传因素（SGE），这些基因会不公平地偏向遗传，以增加其在人群中的传播。尽管具有这种传输优势，但许多 SGE 在自然群体中是短暂的，或者以低于预期的频率被发现。目前尚不清楚哪些因素在野外调节 SGE。我们将研究温度变化对果蝇中自私基因（存在于倒位中）频率的影响，该基因会导致雌性种群性别比例出现偏差，从而可能因缺乏雄性而导致种群灭绝。在美国西北部，这种性别比例扭曲的频率已保持稳定超过 70 年，但观察到的人口梯度的根本原因仍然未知。我们将量化温度梯度范围内自然种群中性别比例扭曲基因频率的变化。一种可能性是，雌性交配行为的变化可能直接调节性比驱动的频率。我们发现，雌性多次交配可以显着降低实验室群体中性别比例扭曲基因的频率。这是由于携带性别比基因的男性与不携带性别比基因的男性相比，精子竞争能力较差。我们将评估温度在改变野生雌性交配频率方面的重要性，以及携带性别比基因的雄性所遇到的精子竞争水平。我们预测低温不利于雄性，因为雌性寿命更长，在较低温度下交配更频繁，因此精子竞争程度更高，从而降低了雄性性别比的亲子关系，阻止了它们的传播。这项研究将提供有关人群适应不断变化的环境的能力的宝贵信息。这可能提供重要信息，说明哪些物种可能成为潜在的农业害虫和疾病媒介，而其他物种则面临灭绝的风险。通过强调雌性交配频率与不利/有利基因传播之间的联系，它对于圈养繁殖计划和生物控制计划也很有价值。