Project description:Social behaviors are essential for survival and reproduction and vary strongly among individuals, species, and heritable brain diseases. The molecular and cellular bases of this variation are poorly resolved, and discovering them is necessary to understand how neural circuit and behavioral functions—and dysfunctions—vary in social contexts. Here we integrate single nucleus RNA-sequencing (snRNA-seq) with comparative genomics and automated behavior analysis to investigate the neurobiology of castle-building, a recently-evolved social, spatial, goal-directed, and repetitive construction behavior in Lake Malawi cichlid fishes. We simultaneously control for and analyze two biological variables correlated with castle-building behavior: quivering, a courtship “dance” behavior, and relative gonadal mass. We find signatures of building-, quivering-, and gonadal-associated neuronal excitation, gene expression, and neurogenesis in distinct cell populations. Converging lines of evidence support the involvement of estrogen, TrkB, and CCK signaling systems, and specific pallial excitatory neuronal subpopulations, in castle-building behavior. We show additional evidence that castle-building has evolved in part through genomic divergence in a gene module that is selectively expressed in stem-like quiescent radial glial cells (RGCs) lining the ventricular zone of the pallium. This RGC subpopulation exhibits signatures of a building-associated departure from quiescence, which in turn is associated with neuronal rebalancing in the putative fish homologue of the hippocampus. Our work supports an unexpected role for glia and neurogenesis in the evolution of social behavior, and more broadly shows how snRNA-seq can be used to systematically profile the cellular bases of previously unstudied social behaviors in new species systems.
Project description:Social behaviors are essential for survival and reproduction and vary strongly among individuals, species, and heritable brain diseases. The molecular and cellular bases of this variation are poorly resolved, and discovering them is necessary to understand how neural circuit and behavioral functions—and dysfunctions—vary in social contexts. Here we integrate single nucleus RNA-sequencing (snRNA-seq) with comparative genomics and automated behavior analysis to investigate the neurobiology of castle-building, a recently-evolved social, spatial, goal-directed, and repetitive construction behavior in Lake Malawi cichlid fishes. We simultaneously control for and analyze two biological variables correlated with castle-building behavior: quivering, a courtship “dance” behavior, and relative gonadal mass. We find signatures of building-, quivering-, and gonadal-associated neuronal excitation, gene expression, and neurogenesis in distinct cell populations. Converging lines of evidence support the involvement of estrogen, TrkB, and CCK signaling systems, and specific pallial excitatory neuronal subpopulations, in castle-building behavior. We show additional evidence that castle-building has evolved in part through genomic divergence in a gene module that is selectively expressed in stem-like quiescent radial glial cells (RGCs) lining the ventricular zone of the pallium. This RGC subpopulation exhibits signatures of a building-associated departure from quiescence, which in turn is associated with neuronal rebalancing in the putative fish homologue of the hippocampus. Our work supports an unexpected role for glia and neurogenesis in the evolution of social behavior, and more broadly shows how snRNA-seq can be used to systematically profile the cellular bases of previously unstudied social behaviors in new species systems.
Project description:This SuperSeries is composed of the following subset Series: GSE33090: Dramatic effects of social behavior on gene regulation in rhesus macaques [Individual_expression] GSE34127: Dramatic effects of social behavior on gene regulation in rhesus macaques [Cell type_expression] GSE34128: Dramatic effects of social behavior on gene regulation in rhesus macaques [Bisulfite_seq] Refer to individual Series
Project description:DNA methylation is an important chromatin modification that is necessary for the structural integrity and proper regulation of the genome for many species. Despite its conservation across the tree of life, little is known about its contribution to complex traits. Reports that differences in DNA methylation between castes in closely related Hymenopteran insects (ants, bees and wasps) contributes to social behaviors has generated hypotheses on the role of DNA methylation in governing social behavior. However, social behavior has evolved multiple times across insecta, and a common role of DNA methylation in social behavior remains outstanding. Using phylogenetic comparative methods we sought to better understand patterns of DNA methylation and social behavior across insects. DNA methylation can be found in social and solitary insects from all orders, except Diptera (flies), which suggests a shared loss of DNA methylation within this order. The lack of DNA methylation is reflected in the absence of the maintenance and de novo DNA methyltransferases (DNMT) 1 and 3, respectively. Interestingly, DNA methylation is found in species without DNMT3. DNA methylation and social behavior (social/solitary) or with division of labor (caste+/caste–) for 123 insect species analyzed from 11 orders are not evolutionary dependent, which is further supported by sequencing of DNA methylomes from 40 species.
Project description:A group of postnatal neurodevelopmental disorders collectively referred to as MeCP2 disorders are caused by aberrations in the gene encoding methyl-CpG-binding protein 2 (MECP2). Loss of MeCP2 function causes Rett syndrome (RTT), whereas increased MeCP2 dosage causes MECP2 duplication or triplication syndromes. MeCP2 acts as a transcriptional repressor, however, the gene expression changes observed in the hypothalamus and cerebellum of MeCP2 disorder mouse models suggest that MeCP2 can also upregulate gene expression. In this study, we compared gene expression changes in the amygdalae of mice lacking MeCP2 (Mecp2-null) and mice overexpressing MeCP2 (MECP2-TG). We chose the amygdala because it is a neuroanatomical region implicated in the control of anxiety and social behavior, two prominent phenotypes in MECP2-TG mice, and hypothesized that transcriptional profiling of this particular brain region may reveal expression changes relevant to heightened anxiety-like behavior and abnormal social behavior. A total of 1,060 genes were altered in opposite directions in both MeCP2 mouse models compared with wild-type littermates, with ~60% up-regulated and ~40% down-regulated. Interestingly, we found a significant enrichment of anxiety- and/or social behavior-related genes among the differentially expressed genes. To determine whether these genes contribute to the anxiety and social behavior phenotypes in MECP2-TG mice, we performed genetic and pharmacologic studies and found that a reduction in Crh suppresses anxiety-like behavior, and a reduction in Oprm1 improves social approach behavior. These studies suggest that MeCP2 impacts molecular pathways involved in anxiety and social behavior, and provide insight into potential therapies for MeCP2 disorders. This study is published in Nature Genetics http://dx.doi.org/10.1038/ng.1066. Total amygdala RNA samples were collected from Mecp2-null male mice (n=4), MECP2-transgenic male mice (n=5), and their wild type male littermates at 6 weeks of age (n=4, n=5 for each group respectively).
Project description:Genetic variation is known to contribute to the variation of animal social behavior, but the molecular mechanisms that lead to behavioral differences are still not fully understood. Here, we investigate the cellular evolution of the hypothalamic medial preoptic area (MPOA), a brain region that plays a critical role in social behavior, across two sister species of deer mice (Peromyscus maniculatus and P. polionotus) with divergent social systems. These two species exhibit large differences in mating and parental care behavior across species and sex. Using single-nucleus RNA-sequencing, we build a molecular atlas of the MPOA for males and females of both Peromyscus species.
Project description:Social interactions can drive distinct gene expression profiles which may vary by social context. Here we use female sailfin molly fish (Poecilia latipinna) to identify genomic profiles associated with preference behavior in distinct social contexts: male-interactions (mate choice) versus female-interactions (shoaling partner preference). We measured behavior of 15 females interacting in a non-contact environment with either two males or two females for 30 minutes followed by whole brain transcriptomic profiling by RNA sequencing. We profiled females that exhibited high levels of social affiliation and great variation in preference behavior to identify an order of magnitude more differentially expressed genes associated with behavioral variation than by differences in social context. Using linear modeling (limma), we took advantage of the individual variation in preference behavior to identify unique gene sets that exhibited distinct correlational patterns of expression with preference behavior in each social context. By combining limma and weighted gene co-expression network analyses (WGCNA) approaches we identify a refined set of 401 genes robustly associated with mate preference that is independent of shoaling partner preference or general social affiliation. While our refined gene set confirmed neural plasticity pathways involved in moderating female preference behavior, we also identified a significant proportion of discovered that our preference-associated genes were enriched for ‘immune system’ gene ontology categories. We hypothesize that the association between mate preference and transcriptomic immune function is driven by the less well-known role of these genes in neural plasticity which is likely involved in higher-order learning and processing during mate choice decisions.