Project description:Metriaclima estherae, Protomelas similis, Rhamphochromis "chilingali", and Astatotilapia tweddlei genomic DNA hybridized with Astatotilapia burtoni genomic DNA 2 Metriaclima estherae vs Astatotilapia burtoni, 2 Protomelas similis vs Astatotilapia burtoni, 2 Rhamphochromis "chilingali" vs Astatotilapia burtoni, and 2 Astatotilapia tweddlei vs Astatotilapia burtoni hybs, all in balanced dye swaps
Project description:Metriaclima estherae, Protomelas similis, Rhamphochromis "chilingali", and Astatotilapia tweddlei genomic DNA hybridized with Astatotilapia burtoni genomic DNA
Project description:Astatotilapia burtoni males change their startle behavior in accordance with changes in a socially-mediated phenotypic state. When dominant (DOM), males are brightly colored, isolated from the school and startle readily in response to an auditory pulse. When subordinate (SUB), males are cryptically colored, school and startle less frequently. We hypothesize that the difference in startle responsiveness is governed by serotonergic modulation on the command-like Mauthner cells (M-cells). We used the selective serotonin receptor subtype 2 (5HTR2) antagonist ketanserin to show that serotonin receptors can modulate startle frequency and that the behavioral difference correlates with differences in electrophysiological recordings of M-cells. Specifically, SUB males have a higher serotonergic tone and demonstrate, by behavior and electrophysiological properties, increased sensitivity to 5-HT manipulations compared to DOMs. Immunohistochemistry for serotonin is present around the M-cells. Furthermore, we identified serotonin receptor transcripts in A. burtoni and used single-cell transcriptomics to determine the presence or absence of specific receptor subtypes in the M-cells. Microarray analysis of M-cell samples shows that the neuron’s transcriptome is relatively stable in individuals of different social status. These results are consistent with a role for serotonin in modulating the behavioral response to sensory stimuli in an ecologically-relevant manner through inhibitory interneurons, which establish the membrane resistance of the M-cell before the auditory stimulus. Simple loop with dye-swap containing 6 arrays from 2 sources with 3 biological replicates per source (3 M-cell and 3 whole brain samples).
Project description:Comparison of social dominance phenotypes induced in the cichlid A. burtoni females with the goal of comparing to other gene expression profiles of social dominance Used platform GPL928 In many species, under varying ecological conditions, social interactions among individuals result in the formation dominance hierarchies. Despite general similarities, there are substantial differences across species, populations, environments, life stages, sexes, and individuals. Understanding the proximate mechanisms of this variation is an important step toward understanding the evolution of social behavior. However, physiological changes associated with dominance such as gonadal maturation and somatic growth, often complicate efforts to identify the specific underlying mechanisms. We demonstrate complementary analysis tools to allow a comparative approach to high-throughput expression profiling that allow us to both test a priori hypotheses and generate new hypotheses about the mechanisms and evolution of social dominance. Using experimental manipulation to produce female dominance hierarchies in the cichlid A. burtoni, heralded as a genomic model of social dominance, we generate gene lists, and assess molecular gene modules. We demonstrate a general pattern of “masculinization” of the female neural gene expression profile and compare expression biases between male and female dominance hierarchies. Using a threshold-free approach to identify correlation throughout gene ranked lists, we query previously published datasets from maternal behavior, alternative reproductive tactics, cooperative breeding and sex-role reversal to describe correlations among neural gene expression profiles. These complementary approaches capitalize on the high-throughput gene expression profiling from similar behavioral phenotypes in order to address the mechanism associated with social dominance behavioral phenotypes.
Project description:Brains from female Astatotilapia burtoni were sampled at four timepoints throughout the reproductive cycle with the primary goal of comparing transcriptome profiles at the different stages and identifying genes and networks involved in parental and fasting behaviors.
Project description:Social plasticity is a pervasive feature of animal behavior. Animals adjust the expression of their social behavior to the daily changes in social life and to transitions between life-history stages, and the ability to change in these ways impacts their Darwinian fitness. This behavioral plasticity may be achieved either by rewiring or by biochemically switching nodes of the neural network underlying the social behavior in response to perceived social information. Independent of the proximate mechanisms, at the neuromolecular level social plasticity relies on the regulation of gene expression, such that different neurogenomic states emerge in response to different social stimuli and the switches between states are orchestrated by signaling pathways that interface the social environment and the genotype. Here, we test this hypothesis by characterizing the changes in the brain profile of gene expression in response to social odors in the Mozambique Tilapia, Oreochromis mossambicus. This species has a rich repertoire of social behaviors during which both visual and chemical information are conveyed to conspecifics. Specifically, dominant males increase their urination frequency during agonist encounters and during courtship to convey chemical information reflecting their dominance status. We recorded electro-olfactograms to test the extent to which the olfactory epithelium can discriminate between olfactory information from dominant and subordinate males as well as from pre- and post-spawning females. We then performed a genome-scale gene expression analysis of the olfactory bulb and the olfactory cortex homolog in order to identify the neuromolecular systems involved in processing these social stimuli. Our results show that different olfactory stimuli from conspecificsM-bM-^@M-^Y have a major impact in the brain transcriptome, with different chemical social cues eliciting specific patterns of gene expression in the brain. These results confirm the role of rapid changes in gene expression in the brain as a genomic mechanism underlying behavioural plasticity and reinforce the idea of an extensive transcriptional plasticity of cichlid genomes, especially in response to rapid changes in their social environment. Brain samples from 40 African cichlid males, Oreochromis mossambicus were collected after stimulation with different social olfactory stimuli. Samples were collected from 2 brain areas: BO and Dp after males were exposed to dominant (DOM) and subordinate (SUB) male urine and pre- (PRE) and post-ovulatory (POST) female scent. In OB 5 replicates were collected from males exposed to DOM and 6 to the other stimuli. For Dp 5 replicates were collected from males exposed to DOM and POST, 4 to SUB and 6 to PRE.
Project description:Astatotilapia burtoni males change their startle behavior in accordance with changes in a socially-mediated phenotypic state. When dominant (DOM), males are brightly colored, isolated from the school and startle readily in response to an auditory pulse. When subordinate (SUB), males are cryptically colored, school and startle less frequently. We hypothesize that the difference in startle responsiveness is governed by serotonergic modulation on the command-like Mauthner cells (M-cells). We used the selective serotonin receptor subtype 2 (5HTR2) antagonist ketanserin to show that serotonin receptors can modulate startle frequency and that the behavioral difference correlates with differences in electrophysiological recordings of M-cells. Specifically, SUB males have a higher serotonergic tone and demonstrate, by behavior and electrophysiological properties, increased sensitivity to 5-HT manipulations compared to DOMs. Immunohistochemistry for serotonin is present around the M-cells. Furthermore, we identified serotonin receptor transcripts in A. burtoni and used single-cell transcriptomics to determine the presence or absence of specific receptor subtypes in the M-cells. Microarray analysis of M-cell samples shows that the neuron’s transcriptome is relatively stable in individuals of different social status. These results are consistent with a role for serotonin in modulating the behavioral response to sensory stimuli in an ecologically-relevant manner through inhibitory interneurons, which establish the membrane resistance of the M-cell before the auditory stimulus.