Genomic basis of honest sexual signalling

雌性经常表现出强烈的性偏好，与展示精致和夸张的性装饰的雄性交配。这些特征被认为是男性遗传质量的真实信号，只有条件好、基因好的男性才能买得起精致的饰品。然而，产生诚实的性信号并使其进化的基因在很大程度上是未知的。因此，性选择和进化的核心有争议的问题仍然没有得到回答，例如性选择在表型细化、分子进化和适应中的作用。回答这些问题是具有挑战性的，因为我们需要对一系列生物体中负责诚实信号的基因进行精确的了解。然而，解构复杂表型以提供单细胞表达数据的新技术现在为探索性特征的基因组基础和进化提供了前所未有的潜力，预示着性选择研究的新纪元。柄眼苍蝇是早期洞察性选择的关键，它有几个重要特征，这些特征赋予了这个支系探索基因组学和诚实信号进化的非凡潜力。与雌性相比，雄性的眼柄非常夸张。眼距是男性状况的真实指标，而女性更喜欢与眼距较长的男性交配。特别是，一些杆眼苍蝇在X染色体上藏匿着一种自私的遗传元素，它会杀死带Y的精子。与标准人群相比，司机群体中的男性遗传质量较低，因为他们一半的精子被破坏。与性选择理论相一致的是，这些男性的眼距较小，对女性的吸引力较小。我们将把最先进的测序方法(scRNA-seq)应用到这一经典的性选择模型中，以探索男性遗传质量和诚实的性信号的基因组基础。具体地说，我们将确定精子发生如何以及何时受到减数分裂驱动因素的干扰，识别与生育力降低相关的基因，并测试这些基因是否不成比例地位于性染色体上。我们的首要目标是确定性别选择的基因组目标，并阐明“好基因”的本质。

Females often show strong sexual preferences to mate with males that exhibit elaborate and exaggerated sexual ornaments. These traits are thought to act as honest signals of male genetic quality, where only high condition males with 'good genes' can afford to invest in elaborate ornaments. However, the genes that give rise to honest sexual signals and enable their evolution are largely unknown. As such, contentious questions central to sexual selection and evolution remain unanswered, such as the role of sexual selection in phenotypic elaboration, molecular evolution and adaptation. Answering these questions is challenging as we require a precise understanding of the genes responsible for honest signals across a range of organisms. However, new technology that deconstructs complex phenotypes to provide single-cell expression data now offers unprecedented potential to probe the genomic basis and evolution of sexual traits, heralding a new era of sexual selection research. The stalk-eyed fly, key to early insights about sexual selection, has several vital characteristics that give the clade exceptional potential to probe the genomics and evolution of honest signalling. Males have highly-exaggerated eye-stalks compared to females. Eye span is an honest indicator of male condition and females prefer to mate with males with longer eye spans. In particular, some stalk-eyed flies harbour a selfish genetic element on the X chromosome that kills Y-bearing sperm. Males from the driver population have lower genetic quality relative to the standard population as half of their sperm are destroyed. Consistent with sexual selection theory, these males exhibit a smaller eye span and are less attractive to females. We will apply state-of-the-art sequencing approaches (scRNA-seq) to this classic model of sexual selection to probe the genomic basis of male genetic quality and honest sexual signalling. Specifically, we will establish how and when spermatogenesis is disrupted in response to the meiotic driver, identify the genes associated with reduced fertility, and test whether these genes are disproportionally located on the sex chromosomes. Our overarching goal is to identify the genomic targets of sexual selection and elucidate the very nature of 'good genes'.