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: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=589053
• 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.

我小组的研究重点关注生物学中三个最重要的未解决问题：（1）为什么大多数物种都有性繁殖和两种性别，而不是无性繁殖且只有雌性； (2) 新物种是如何起源的； （3）人们的认知特征（心理特征和能力）如何以及为何存在差异，以及不同的技能是否倾向于相互权衡。 (1) 有性生殖与无性生殖。 大多数动物有两种性别。 这种模式很不寻常，因为只有雌性才能产生后代，而任何产生所有女儿（没有交配）的雌性所生的孙子数量是拥有一半儿子和一半女儿的雌性的两倍。 因此，理论预测所有物种都应该是无性的并且全是雌性，除非有性繁殖有很大的好处，或者无性繁殖有很大的长期成本。 我们研究了一群昆虫，其中无性生殖至少进化了七次，并通过有丝分裂（自我克隆）发生。 在这些昆虫中，我们（1）进行基因测序和系统发育工作，使我们能够推断无性昆虫是否真的在野外的后代生产中具有很大优势，（2）确定无性昆虫的后代新突变率是否比有性昆虫低，因为它们进行克隆，（3）评估无性昆虫是否更擅长DNA修复，或者对DNA损伤更有抵抗力，以及 （4）研究它们的免疫系统基因是如何进化的，因为无性动物可能已经进化出新的基因抵抗寄生虫的方式。 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)新物种的起源。 确定新的生物多样性如何产生是生物学中的一个基本问题。 物种是个体可以成功交配并产生可育后代的种群。 我们正在一组昆虫中研究这一过程，其中每个物种都以不同种类的植物为食，并且它们非常适应这些植物。 寄主植物的变化与新物种的形成有关。 在这些昆虫中，交配部分基于气味：个体体表上的一组化学物质。 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特征中的作用，通过在不同的寄主植物上饲养个体并量化它们的化学特征及其相互交配的倾向。 这些研究将揭示寄主植物变化和化学信号在新昆虫物种产生中的作用。 研究结果对于理解生态和行为特征如何参与物种起源具有普遍重要意义。 (3)认知特征的进化。 人类具有非凡的认知能力，无论是与其他人类的社交互动，还是视觉空间技能和技术等非社交能力。 我们开发了一种人类认知模型，其核心是社会和非社会能力和兴趣之间权衡的重要作用，这样一个领域的增强往往会伴随着另一个领域的减少。 该模型得到了心理学、神经科学和精神病学的一系列数据的支持，但尚未经过直接测试。 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型是否介导社交（相对于非社交）兴趣和技能。 这些结果将对理解人脑如何工作以及人类精神障碍如何发展具有重要意义。