Evolution of species interactions in adaptive radiation

适应性辐射中物种相互作用的演变

• 批准号: RGPIN-2021-03177
• 负责人: Schluter, Dolph
• 金额: $ 6.92万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=766139
• 关键词: Evolution; species; interactions; adaptive; radiation

My research program investigates the causes of adaptive radiation, defined as the evolution of ecological diversity in a rapidly diversifying lineage. I propose to carry out experiments to test mechanisms of selection on genes and genomes. My main study organism is threespine stickleback fish, a supermodel organism having many experimental advantages and exhibiting rampant parallel evolution, aiding comparative phenotypic and genomic studies. I describe three major projects. 1) Character displacement and reproductive isolation. Evolution of competitive interactions is a hallmark of adaptive radiation. However, there are as yet no experimental tests of whether resource competition drives evolution in a natural system. The contribution of competition to evolution of reproductive isolation (speciation) is even less well understood. Conflicting theories of adaptive radiation differ by whether character displacement is an integral part of speciation or occurs later. We will use a pond evolution experiment with stickleback to test whether competition leads to divergent evolution in the same regions of the genome already known to underlie niche divergence and assortative mating.  2) The evolution of hybrid genomes. Postzygotic reproductive isolation is hypothesized to evolve more slowly than premating isolation and to play a reduced role early in speciation.  We propose three investigations of the role of gene-gene incompatibilities in hybrids of young stickleback species. First, we will use a pond experiment to test the prediction that gene-gene incompatibilities in F2 hybrids should favor increased heterozygosity genome-wide. Second, we will measure the direction of evolution of minor-parent alleles in wild hybrid populations. Third, we will conduct a multigenerational experimental test of the prediction that that gene-gene incompatibilities should favor major-parent alleles in experimental backcross populations introduced to ponds. Gene-gene interactions are predicted to select against minor parent alleles because they experience more potential antagonistic interactions with major parent alleles regardless of which species is the minor parent. In contrast, ecological adaptation should result in parallel evolution of allele frequencies between populations regardless of major and minor parent allele frequencies. 3) Maintenance of standing genetic variation. The leading hypothesis for the maintenance of standing genetic variation in colonizing populations is that allele frequency is a balance between migration and selection. We will test two unique predictions of this hypothesis for maintaining freshwater alleles in marine threespine stickleback. We will use a bank of 1000 stickleback genome sequences to test if freshwater allele copies in marine individuals have a nearby freshwater source. Second, we will test whether freshwater allele copies found in the sea show a genomic signature of having arrived in the sea only relatively recently.

我的研究项目调查适应性辐射的原因，其定义为快速多样化的谱系中生态多样性的进化。我建议进行实验来测试基因和基因组的选择机制。我的主要研究生物是三刺刺鱼，一种超级模型。生物体具有许多实验优势并表现出猖獗的平行进化，有助于比较表型和基因组研究1）竞争性相互作用的进化是适应性辐射的标志。迄今为止，还没有关于资源竞争是否推动自然系统进化的实验测试，人们对竞争对生殖隔离（物种形成）进化的贡献更是了解甚少。我们将使用棘鱼的池塘进化实验来测试竞争是否会导致已知的生态位分歧和选型交配背后的基因组的趋异进化。 2）杂种基因组的进化。生殖隔离比交配前隔离进化得更慢，并且在物种形成早期发挥的作用减弱。我们提出了三项关于基因-基因不相容性在幼刺鱼杂交中的作用的研究。预测 F2 杂种中的基因-基因不相容性应有利于全基因组杂合性的增加。 其次，我们将测量野生杂种群体中次要亲本等位基因的进化方向。多代实验测试预测，在引入池塘的实验回交群体中，基因-基因不相容性应有利于主要亲本等位基因。基因-基因相互作用预计会选择次要亲本等位基因，因为无论如何，它们都会与主要亲本等位基因经历更多潜在的拮抗相互作用。相反，无论主要和次要亲本等位基因频率如何，生态适应都会导致种群之间等位基因频率的平行进化。3）维持遗传变异。​维持遗传变异的主要假设。定植种群中存在的遗传变异是等位基因频率是迁移和选择之间的平衡，我们将测试该假设的两个独特预测，以维持海洋三刺棘鱼的基因组序列。其次，我们将测试在海洋中发现的淡水等位基因拷贝是否显示出最近才到达海洋的基因组特征。