Sexual reproduction is pervasive in animals and has led to the evolution of sexual dimorphism. In most animals, males and females show marked differences in primary and secondary sexual traits. The formation of sex-specific organs and eventually sex-specific behaviors is defined during the development of an organism. Sex determination processes have been extensively studied in a few well-established model organisms. While some key molecular regulators are conserved across animals, the initiation of sex determination is highly diverse. To reveal the mechanisms underlying the development of sexual dimorphism and to identify the evolutionary forces driving the evolution of different sexes, sex determination mechanisms must thus be studied in detail in many different animal species beyond the typical model systems. In this perspective article, we argue that spiders represent an excellent group of animals in which to study sex determination mechanisms. We show that spiders are sexually dimorphic in various morphological, behavioral, and life history traits. The availability of an increasing number of genomic and transcriptomic resources and functional tools provides a great starting point to scrutinize the extensive sexual dimorphism present in spiders on a mechanistic level. We provide an overview of the current knowledge of sex determination in spiders and propose approaches to reveal the molecular and genetic underpinnings of sexual dimorphism in these exciting animals.

中文翻译：

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蜘蛛的性别差异：从表型到基因组学。

有性生殖在动物中无处不在，并导致了性二态性的进化。在大多数动物中，雄性和雌性在主要和次要性特征上表现出明显差异。在生物体的发育过程中定义了特定性别器官的形成以及最终的特定性别行为。在一些公认的模型生物中，对性别确定过程进行了广泛的研究。尽管一些关键的分子调节剂在整个动物中都是保守的，但性别决定的启动是高度多样的。为了揭示性二态性发展的基础机制并确定驱动不同性别进化的进化力，因此必须在典型模型系统之外的许多不同动物物种中详细研究性别决定机制。在这篇观点文章中，我们认为，蜘蛛代表了研究性别决定机制的优秀动物。我们表明，蜘蛛在各种形态，行为和生活史特征上都是性二态的。越来越多的基因组和转录组资源以及功能性工具的可用性为从机械角度研究蜘蛛中广泛存在的性二态性提供了一个很好的起点。我们提供了有关蜘蛛中性别确定的最新知识的概述，并提出了揭示这些令人兴奋的动物中性二态性的分子和遗传基础的方法。越来越多的基因组和转录组资源以及功能性工具的可用性为从机械角度研究蜘蛛中广泛存在的性二态性提供了一个很好的起点。我们提供了有关蜘蛛中性别确定的当前知识的概述，并提出了揭示这些令人兴奋的动物中性二态性的分子和遗传基础的方法。越来越多的基因组和转录组资源以及功能性工具的可用性为从机械角度研究蜘蛛中广泛存在的性二态性提供了一个很好的起点。我们提供了有关蜘蛛中性别确定的最新知识的概述，并提出了揭示这些令人兴奋的动物中性二态性的分子和遗传基础的方法。