Inventing monogamy: innovation and adaptation in the epigenome

新的行为是如何演变的？最近的技术进步使我们能够确切地问出，在基因表达、神经功能和复杂行为方面，哪些脱氧核糖核酸(DNA)序列是进化创新的基础。一个有机体与另一个个体形成联系的能力是一种复杂的行为，它塑造了包括人类在内的许多物种所表现出的社会行为。在目前的项目中，研究人员确定了进化适应，这是一种研究得很好的物种--一夫一妻制草原田鼠--社会纽带的基础。研究人员比较了区分一夫一妻制草原田鼠和混血亲戚的DNA序列的细微变化。他们还问，DNA的这些变化是否会影响大脑中对配对结合至关重要的区域以及对空间记忆重要的大脑区域的基因功能，因为空间使用是动物交配系统中的一个主要因素。最后，研究人员通过检查DNA变异的模式，询问自然选择是否对这些DNA序列起作用。这些发现将有助于理解复杂行为的变化是如何从DNA的变异中出现的。为了完成研究，调查人员将从代表性不足的群体中招聘和培训本科生。此外，研究人员将开发和传播对各种物种进行类似研究所需的研究工具，使对任何物种的基因组功能和行为进行尖端研究变得更容易。从这项工作中得到的答案将阐明行为和导致多样性和疾病的微妙遗传变异之间的关系。一个现有的基因型是如何一个座位一个座位地塑造出来的，以产生新的表型？研究人员使用田鼠属作为理解导致社会一夫一妻制的表观遗传创新的模型，建立在社会神经科学、分子遗传学和行为生态学的广泛工作基础上。他们研究了三种田鼠的表观基因组及其进化：一夫一妻制的草原田鼠M.ochrogaster；混杂的草甸田鼠M.pennsylvanicus；以及混杂的外群加州田鼠M.calforNicus。尽管许多大脑区域值得研究，但研究人员将重点放在四个大脑区域：奖赏结构(伏隔核、苍白球腹侧)和空间记忆结构(海马体、脾后皮质)。在第一个目标中，他们使用RNA-SEQ和CHIP-SEQ来识别基因调控中的物种差异。在第二个目标中，他们使用系统发育和种群遗传学方法来识别表观基因组中的适应。这两个数据集的交集将识别可能与配对-键的形成以及空间认知中的交配系统差异相关的调控区域。最后，研究人员测试了这一群体中一夫一妻制的演变是否主要依赖于与结合有关的变化，与认知有关的变化，还是两者都依赖。识别出的DNA序列可以在未来的研究中进行操纵。

How do new behaviors evolve? Recent technical advances allow us to ask exactly which deoxyribonucleic acid (DNA) sequences underlie evolutionary innovations in gene expression, neural function, and complex behaviors. The ability of an organism to form a bond with another individual is a complex behavior, one that shapes the social behaviors exhibited by many species, including humans. In the current project, the investigators identify evolutionary adaptations that underlie social bonding in a well-studied species, the monogamous prairie vole. The investigators compare the subtle changes in DNA sequences that distinguish monogamous prairie voles from promiscuous relatives. They also ask whether these changes in DNA influence gene function in brain regions important for pair-bonding as well as brain regions important for spatial memory because space use is a major factor in animal mating systems. Lastly, the investigators ask whether natural selection has operated on these DNA sequences by examining patterns of DNA variation. The findings will help understand how changes in complex behavior can emerge from variation in DNA. To complete the studies, the investigators will recruit and train undergraduates from under-represented groups. Further, the investigators will develop and disseminate research tools needed to perform similar studies on a great variety of species, making it easier to do cutting-edge studies of genome function and behavior in any species. The answers obtained from this work will elucidate the relation between behavior and subtle genetic variations that contribute to diversity and disease.How is an existing genotype sculpted, locus by locus, to result in a new phenotype? The investigators use the genus Microtus as a model for understanding the epigenetic innovations that gave rise to social monogamy, building on an extensive body of work in social neuroscience, molecular genetics, and behavioral ecology. They examine the epigenome and its evolution in three vole species: the monogamous prairie vole, M. ochrogaster; the promiscuous meadow vole, M. pennsylvanicus; and a promiscuous outgroup, the California vole, M. californicus. Although many brain regions merit study, the investigators focus on four brain regions: reward structures (nucleus accumbens, ventral pallidum) and spatial memory structures (hippocampus, retrosplenial cortex). In the first aim, they use RNA-seq and ChIP-seq to identify species differences in gene regulation. In second aim, they use phylogenetic and population genetic methods to identify adaptations within the epigenome. The intersection of these two data sets will identify regulatory regions likely to be causally involved in pair-bond formation, and in mating system differences in spatial cognition. Finally, the investigators test whether the evolution of monogamy in this group relied predominantly on changes related to bonding, to cognition, or both. The identified DNA sequences can then be subject to manipulation in future studies.