Tradeoffs, Conflicts and Cooperation in the Evolution of Behaviour and Reproduction

行为和繁殖进化中的权衡、冲突与合作

• 批准号: RGPIN-2014-06505
• 负责人: Crespi, Bernard
• 金额: $ 4.52万
• 依托单位: Simon Fraser University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=612267
• 关键词: Tradeoffs; Conflicts; Cooperation; Evolution; Behaviour

The research in my group focuses on three of the most important unresolved questions in biology: (1) why most species have sexual reproduction and two sexes, rather than asexual reproduction and only females; (2) how new species originate; and (3) how and why people differ in cognitive traits (mental traits and abilities), and if different skills tend to trade off with one another. (1) Sexual versus asexual reproduction. Most animals have two sexes. This pattern is unusual because only females produce offspring, and any female that produced all daughters (without mating) could have twice as many grand-offspring as a female who had half sons and half daughters. Theory thus predicts that all species should be asexual and all-female, unless there are large benefits to reproducing sexually, or large, long-term costs to reproducting asexually. We study of group of insects in which asexuality has evolved at least seven times, and occurs by mitosis (self-cloning). In these insects, we are (1) conducting gene-sequencing and phylogenetic work that allows us to infer whether or not asexuals really have a large advantage in offspring production, in the field, (2) determining whether asexuals have lower rates of new mutations in their offspring than do sexuals, because they undergo cloning, and (3) evaluating if asexuals are better at DNA repair, or more resistant to DNA damage, and (4) studying how their immune system genes evolve, because asexuals may have evolved new ways of genetically-resisting parasites. These studies will help us to understand why sex predominates in animals, and how good and bad mutations originate and evolve. (2) Origins of new species. Determining how new biodiversity arises is a fundamental question in biology. Species are populations within which individuals can successfully mate and produce fertile offspring. We are studying this process in a group of insects where each species lives on different species of plants, to which they are closely adapted. Host plant changes are associated with the formation of new species. In these insects, mating is based in part on smell: the set of chemicals that individuals have on their body surfaces. We have shown that divergence in these chemicals is positively correlated with divergence in tendencies to mate. We are now studying the roles of host plants in chemical profiles of individuals, by rearing individuals on different host plants and quantifying their chemical profiles and their tendencies to mate with one another. These studies will uncover the roles of host plant changes, and chemical signals, in the generation of new species of insects. The results will be of general importance to understanding how ecological and behavioral traits are involved in origins of species. (3) Evolution of cognitive traits. Humans have extraordinary cognitive abilities, with regard to both social interactions with other humans, and with regard to non-social abilities such as visual-spatial skills and technology. We have developed a model of human cognition that centres on an important role for tradeoffs between social and non-social abilities and interests, such that enhancements in one domain tend to go along with reductions in the other. This model is supported by a suite of data from psychology, neuroscience and psychiatry, but has yet to be tested directly. We are genotyping large numbers of individuals for a set of genes that are involved in social and non-social cognition, to determine if alternative alleles and genotypes for such genes mediate social, relative to non-social, interests and skills. The results will have important implications for understanding how the human brain works, and how human mental disorders can develop.

我所在团队的研究集中在生物学中最重要的三个悬而未决的问题上：(1)为什么大多数物种都有有性繁殖和双性繁殖，而不是无性繁殖和只有雌性；(2)新物种是如何起源的；(3)人们在认知特征(心理特征和能力)上如何以及为什么会不同，不同的技能是否倾向于相互取舍。 (1)有性生殖与无性生殖。大多数动物有两种性别。这种模式是不寻常的，因为只有雌性才能生育后代，任何生下所有女儿的雌性(没有交配)的孙辈可能是有半个儿子和半个女儿的雌性的两倍。因此，理论预测，所有物种都应该是无性和全雌性的，除非有性繁殖有很大的好处，或者无性繁殖的长期成本很高。 我们研究了一组昆虫，在这些昆虫中，无性至少进化了七次，并通过有丝分裂(自克隆)发生。在这些昆虫中，我们正在(1)进行基因测序和系统发育工作，以便我们在野外推断无性恋者在后代生产中是否真的具有很大的优势，(2)确定无性恋者的后代是否因为进行克隆而在后代中有更低的新突变率，(3)评估无性恋者是否更善于DNA修复，或更能抵抗DNA损伤，以及(4)研究它们的免疫系统基因是如何进化的，因为无性恋者可能进化出了抵抗遗传的寄生虫的新方法。这些研究将帮助我们理解为什么性别在动物中占主导地位，以及好的和坏的突变是如何起源和进化的。 (2)新种的起源。确定新的生物多样性是如何产生的是生物学中的一个基本问题。物种是个体能够在其中成功交配并产生可生育后代的种群。我们正在一组昆虫中研究这一过程，每种昆虫都生活在不同的植物物种上，它们对这些植物有密切的适应。寄主植物的变化与新物种的形成有关。在这些昆虫中，交配部分是基于气味：个体身体表面的一组化学物质。我们已经证明，这些化学物质的差异与交配倾向的差异呈正相关。 我们现在正在研究寄主植物在个体化学图谱中的作用，方法是将个体饲养在不同的寄主植物上，并量化它们的化学图谱及其相互交配的趋势。这些研究将揭示寄主植物变化和化学信号在昆虫新物种产生中的作用。这一结果将对理解生态和行为特征如何与物种起源有关具有普遍意义。 (3)认知特质的演变。人类拥有非凡的认知能力，既包括与他人的社会互动，也包括视觉空间技能和技术等非社会能力。我们已经开发了一个人类认知模型，它围绕着社会和非社会能力和利益之间的权衡发挥重要作用，因此在一个领域的增强往往伴随着另一个领域的减少。这一模型得到了心理学、神经科学和精神病学的一系列数据的支持，但尚未得到直接测试。我们正在对大量个体的一组涉及社会和非社会认知的基因进行基因分型，以确定这些基因的替代等位基因和基因类型是否相对于非社会兴趣和技能起到了调节社会兴趣和技能的作用。这一结果将对理解人脑是如何工作的，以及人类精神障碍是如何发展的具有重要意义。