Collaborative Research: Behavioral Syndromes as Evolutionary Constraints: the Role of Genetic Architecture

在这个项目中，Dochtermann博士和Hedrick博士将研究行为之间相互关联的进化原因和结果。现在人们已经很好地理解了单个动物的行为通常是相关的，之前的大多数研究都集中在描述这些相关性上。对于理解为什么行为是相关的，人们的注意力要少得多。对于为什么行为可能是相关的，通常有两种解释。首先，可能存在相关性，因为特定的行为组合在进化上受到了青睐(即选择)。其次，潜在的分子机制，如单个基因影响多种行为，可能会产生相关性。通过比较种群间的遗传相关性，PI将尝试查看选择是否形成了相关性。随后，研究人员将进行一项人工选择实验，目的是打破行为的相关性。这项人工选择实验将提供关于上述任何一种解释可能在多大程度上产生行为相关性的额外证据。此外，这项实验将阐明行为相关性影响和制约进化结果的程度。尽管行为综合征，即个体之间的行为相关性，现在已经在跨分类群中得到了很好的描述，但对综合征的进化原因和后果仍然知之甚少。综合征的进化原因一般可归结为两类机制：选择诱导的连锁不平衡(SILD)，其中特定的行为组合受到青睐；以及分子机制，如多效性。这两类机制具有非常不同的进化含义。如果多效性等分子机制是综合征的基础，那么可能会对SILD不存在的进化结果施加限制(重要的是，这些机制并不是相互排斥的，因为两者都可能共同影响综合征的表达)。在这个项目中，研究人员将进行种群比较和人工选择实验，以区分这两类机制。具体地说，将估计多个种群的遗传相关性和遗传力，并与生态变量进行比较。如果种群不同，选择压力可能有利于种群之间不同的行为组合，则这些比较可以检测到SILD。后续的人工选择实验旨在打破行为相关性，将评估症状的约束效应，种群对人工选择的反应能力将区分SILD和分子机制。

In this project, the Drs. Dochtermann and Hedrick will study the evolutionary causes and consequences of correlations among behaviors. It is now well understood that the behaviors of individual animals are often correlated, and most previous research has focused on characterizing these correlations. Much less attention has been paid to understanding why behaviors are correlated. There are generally two explanations for why behaviors might be correlated. First, correlations might be present because particular combinations of behaviors have been evolutionarily favored (i.e. selection). Second, underlying molecular mechanisms,such as a single gene affecting multiple behaviors,might produce correlations. By comparing genetic correlations among populations, the PIs will attempt to see if selection has shaped correlations or not. Following this, the researchers will conduct an artificial selection experiment with the aim of breaking apart behavioral correlations. This artificial selection experiment will provide additional evidence regarding the degree to which either of the above explanations might produce behavioral correlations. Moreover, this experiment will illustrate the degree to which behavioral correlations affect and constrain evolutionary outcome.Although Behavioral Syndromes, among-individual behavioral correlations, are now well described across taxa, the evolutionary causes and consequences of syndromes are still poorly understood. The evolutionary causes of syndromes can generally be grouped into two classes of mechanisms: selection-induced linkage disequilibrium (SILD) wherein particular combinations of behaviors have been favored, and molecular mechanisms such as pleiotropy. These two classes of mechanisms have very different evolutionary implications. If molecular mechanisms such as pleiotropy underlie syndromes, then constraints may be placed on evolutionary outcomes which are not present with SILD (importantly, these mechanisms are not mutually exclusive, as both may jointly influence the expression of syndromes). In this project, the researchers will conduct population comparisons and artificial selection experiments to distinguish between these two classes of mechanisms. Specifically, genetic correlations and heritabilities of multiple populations will be estimated and compared relative to ecological variables. These comparisons can allow the detection of SILD if the populations differ such that selective pressures might favor different combinations of behaviors among populations. Follow up artificial selection experiments designed to break apart behavioral correlations will estimate the constraining effect of syndromes, and the ability of populations to respond to artificial selection will distinguish between SILD and molecular mechanisms.