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.
Project description:Background The evolution of female choice mechanisms favouring males of their own kind is considered as crucial step during the early stages of speciation. However, although the genomics of mate choice may influence both the likelihood and speed of speciation, the identity and location of genes underlying assortative mating remain largely unknown. Methods and Findings We used mate choice experiments and gene expression analysis of female D. melanogaster to examine three key components influencing speciation. We show that the 1,498 genes in Zimbabwean female Drosophila melanogaster whose expression levels differ when mating with more (Zimbabwean) versus less (Cosmopolitan strain) preferred males include many with high expression in the central nervous system and ovaries, are disproportionately X-linked and form a number of clusters with low recombination distance. Significant involvement of the brain and ovaries is consistent with the action of a combination of pre- and postcopulatory female choice mechanisms, while sex linkage and clustering of genes lead to high potential evolutionary rate and sheltering against the homogenizing effects of gene exchange between populations. Conclusion Taken together our results imply favourable genomic conditions for the evolution of reproductive isolation through mate choice in Zimbabwean D. melanogaster and suggest that mate choice may, in general, act as an even more important engine of speciation than previously realized.
Project description:The evolution of female choice mechanisms favouring males of their own kind is considered as crucial step during the early stages of speciation. However, although the genomics of mate choice may influence both the likelihood and speed of speciation, the identity and location of genes underlying assortative mating remain largely unknown. We used mate choice experiments and gene expression analysis of female D. melanogaster to examine three key components influencing speciation. We show that the 1,498 genes in Zimbabwean female Drosophila melanogaster whose expression levels differ when mating with more (Zimbabwean) versus less (Cosmopolitan strain) preferred males include many with high expression in the central nervous system and ovaries, are disproportionately X-linked and form a number of clusters with low recombination distance. Significant involvement of the brain and ovaries is consistent with the action of a combination of pre- and post-copulatory female choice mechanisms, while sex linkage and clustering of genes lead to high potential evolutionary rate and sheltering against the homogenizing effects of gene exchange between populations. Taken together our results imply favourable genomic conditions for the evolution of reproductive isolation through mate choice in Zimbabwean D. melanogaster and suggest that mate choice may, in general, act as an even more important engine of speciation than previously realized. We measured gene expression of adult female Drosophila melanogaster from a composite Zimbabwe (Z) strain population named SZ, produced by mixing the genomes of six Z strain isofemale lines, shortly after mating them with either SZ strain or cosmopolitan (M strain) males. Data from four replicates of each of the two treatments (SZ mated with SZ; SZ mated with M) are presented, giving a total of eight arrays.
Project description:Mate choice plays a fundamental role in speciation, yet we know little about the molecular mechanisms that underpin this crucial decision-making process. Stickleback fish differentially adapted to limnetic and benthic habitats are reproductively isolated and females of each species use different male traits to evaluate prospective partners and reject heterospecific males. Here, we integrate behavioral data from a mate choice experiment with gene expression profiles from the brains of females actively deciding whether to mate. We find substantial gene expression variation between limnetic and benthic females, regardless of behavioral context, suggesting general divergence in constitutive gene expression patterns, corresponding to their genetic differentiation. Intriguingly, female gene co-expression modules covary with male display traits but in opposing directions for sympatric populations of the two species, suggesting male displays elicit a dynamic neurogenomic response that reflects known differences in female preferences. Furthermore, we confirm the role of numerous candidate genes previously implicated in female mate choice in other species, suggesting that evolutionary tinkering with these conserved molecular processes underlies divergent mate preferences and sexual isolation. Taken together, our study adds important new insights to our understanding of the molecular processes underlying female decision-making critical for generating sexual isolation and speciation.
Project description:Mating systems have broad impacts on how sexual selection and mate choice operate within a species, but studies of mating behavior in the laboratory may not reflect how these processes occur in the wild. Here, we examined the mating behavior of the neotropical butterfly Heliconius erato in the field by releasing larvae and virgin females and observing how they mated. H. erato is considered a pupal-mating species (i.e., males mate with females as they emerge from the pupal case). However, we observed only two teneral mating events, and experimentally released virgins were almost all mated upon recapture. Our study confirms the presence of some pupal-mating behavior in H. erato, but suggests that adult mating is likely the prevalent mating strategy in this species. These findings have important implications for the role of color pattern and female mate choice in the generation of reproductive isolation in this diverse genus.
Project description:Sexual selection involves mate preference behavior and is a critical determinant for natural selection and evolutionary biology. Previously an environmental compound (fungicide vinclozolin) was found to promote epigenetic transgenerational inheritance of modified mate selection characteristics in all progeny for three generations after exposure of a gestating female. The current study investigated gene networks involved in various regions of the brain that correlated with the mate preference behavior altered in F3-Vinclozolin lineage animals. Statistically significant correlations of differentially expressed gene clusters and modules were identified to associate with specific mate preference behaviors. This novel systems biology approach identified critical gene networks involved in mate preference behavior and demonstrated the ability of environmental factors to promote epigenetic transgenerational inheritance of this altered evolutionary biology determinant. Combined observations elucidate the potential molecular control of mate preference behavior and suggests environmental epigenetics can have a role in evolutionary biology. We used Affymetrix Rat Gene 1.0 ST microarrays to determine genes expressed differentially in F3 Vinclozolin lineage male or female rats' 6 brain areas - amygdala (Amy), hippocampus (Hipp), olfactory bulb (OlfB), cingulate cortex (CngCtx), entorhinal cortex (EnCtx), and preoptic area-anterior hypothalamus (POAH) - due to Vinclozolin treatments of their grand-grandmothers (F0).
Project description:Many animal species remain separate not because their individuals fail to produce viable hybrids but because they "choose" not to mate. However, we still know very little of the genetic mechanisms underlying changes in these mate preference behaviours. Heliconius butterflies display bright warning patterns, which they also use to recognize conspecifics. Here, we couple QTL for divergence in visual preference behaviours with population genomic and gene expression analyses of neural tissue (central brain, optic lobes and ommatidia) across development in two sympatric Heliconius species. Within a region containing 200 genes, we identify five genes that are strongly associated with divergent visual preferences. Three of these have previously been implicated in key components of neural signalling (specifically an ionotropic glutamate receptor and two regucalcins), and overall our candidates suggest shifts in behaviour involve changes in visual integration or processing. This would allow preference evolution without altering perception of the wider environment.
Project description:Sexual selection involves mate preference behavior and is a critical determinant for natural selection and evolutionary biology. Previously an environmental compound (fungicide vinclozolin) was found to promote epigenetic transgenerational inheritance of modified mate selection characteristics in all progeny for three generations after exposure of a gestating female. The current study investigated gene networks involved in various regions of the brain that correlated with the mate preference behavior altered in F3-Vinclozolin lineage animals. Statistically significant correlations of differentially expressed gene clusters and modules were identified to associate with specific mate preference behaviors. This novel systems biology approach identified critical gene networks involved in mate preference behavior and demonstrated the ability of environmental factors to promote epigenetic transgenerational inheritance of this altered evolutionary biology determinant. Combined observations elucidate the potential molecular control of mate preference behavior and suggests environmental epigenetics can have a role in evolutionary biology. We used Affymetrix Rat Gene 1.0 ST microarrays to determine genes expressed differentially in F3 Vinclozolin lineage male or female rats' 6 brain areas - amygdala (Amy), hippocampus (Hipp), olfactory bulb (OlfB), cingulate cortex (CngCtx), entorhinal cortex (EnCtx), and preoptic area-anterior hypothalamus (POAH) - due to Vinclozolin treatments of their grand-grandmothers (F0). For each of 6 brain areas of male or female rats (female: amygdala (F-Amy), cingulate cortex (F-CngCTX), enterorhinal cortex (F-EnCTX), hippocampus (F-Hipp), olfactory bulbs (F-OlfB), and preoptic area-anterior hypothalamus (F-POAH); male: amygdala (M-Amy), cingulate cortex (M-CngCTX), enterorhinal cortex (M-EnCTX), hippocampus (M-Hipp), olfactory bulbs (M-OlfB), and preoptic area-anterior hypothalamus (M-POAH)), RNA samples from 2 treatment groups - F3 Control lineage (Con) or F3 Vinclozolin lineage (Vin) - were compared to each other. Each of treatment groups contained 4-6 biological replicas for each brain region. RNA for each replica was isolated from an individual animal in order to compare to individual animal mate preference behavior studied with the same rats before sacrifice. Totally, 132 RNA samples from 24 animals (6 male F3 Control, 6 male F3 Vinclozolin,6 female F3 Control, and 6 female F3 Vinclozolin) were isolated and studied.
Project description:Visual deprivation, either in the form of dark rearing (DR) or monocular deprivation (MD) are established paradigms for studying cortical plasticity. We have used miRNA microarray to uncover miRNAs whose expression is altered in primary visual cortex following DR and/or MD. C57BL6 mice were reared in normal light and dark conditions (control) till P28, in complete darkness since birth (DR) till P28, or were grown in normal light/dark conditions from birth till P24 and then subjected to lid suturing of one eye till P28. Mice were euthanized at P28 and their primary visual cortex areas were excised and subjected to RNA isolation. In the case of MD mice only the contralateral to lid suture primary visual cortex was extracted. 100ng of total RNA (tested and quantified using the Agilent Bioanalyzer 2100) were labeled using the Agilent miRNA labeling system and hybridized to Agilent murine miRNA arrays. Microarrays were hybridized overnight at 64 ºC, scanned using an Agilent scanner and extracted with Agilent feature extractor 10.1.