Project description:In the fire ant Solenopsis invicta, a chromosomal inversion-derived supergene predicts gyne (pre-reproductive queen) weight and corresponding colony founding behavior. Inversion-carrying gynes are lightweight and depend on assistance from workers, meaning they must initiate reproduction in an already existing social group. Gynes that lack the inversion supergene are heavier and found colonies from scratch, relying on their own nutrient reserves to feed an initial brood. However, plasticity in gyne weight and life history also exists in fire ants, such as queen replacement, an alternative mode of dependent reproduction determined by gyne overwintering status. Like inversion-carrying gynes, overwintered gynes without the inversion supergene exhibit a lightweight phenotype and worker dependence. In gyne brains and ovaries, we compared transcriptional profiles of overwintered and non-overwintered gynes to reveal the gene regulatory changes associated with overwintering. We observed functional enrichment for several biological processes related to metabolism and behavior among these plasticity-associated differentially expressed genes. A comparison to genes differentially expressed by supergene genotype revealed significantly greater overlap than expected by chance in ovarian tissues. Moreover, some plasticity-associated genes were found to exhibit fixed allelic differences between inverted and non-inverted supergene variants that may contribute to observed differences in gene expression and physiology. Overall, our results are consistent with the hypothesis that a supergene modulates variation in social organization, in part, through increased genetic regulation of ancestrally plastic traits.
Project description:To investigate the effect of supergene status and social environment pre- and post-pupation, we used RNA-sequencing of fire ant ant workers to assess gene expression differences.
Project description:Performances of flax gene expression analyses were compared in two categories of Nimblegen microarrays (short 25-mers oligonucleotides and long 60-mers oligonucleotides) Results obtained in this study are described in Intra-platform comparison of flax (Linum usitatissimum L.) high-density Nimblegen DNA microarrays submitted to Journal of Computational Biology
Project description:Using an organ-specific RNA-sequencing approach, we explore the role of supergene genotype and social environment on unmated, reproductive females Solenopsis invicta ants as they depart on their mating flights.
Project description:Chromatin accessibility is an important functional genomics phenotype that influences transcription factor binding and gene expression. Genome-scale technologies allow chromatin accessibility to be mapped with high-resolution, facilitating detailed analyses into the genetic architecture and evolution of chromatin structure within and between species. We performed Formaldehyde-Assisted Isolation of Regulatory Elements sequencing (FAIRE-Seq) to map chromatin accessibility in two parental haploid yeast species, Saccharomyces cerevisiae and Saccharomyces paradoxus and their diploid hybrid. We show that although broad-scale characteristics of the chromatin landscape are well conserved between these species, accessibility is significantly different for 947 regions upstream of genes that are enriched for GO terms such as intracellular transport and protein localization exhibit. We also develop new statistical methods to investigate the genetic architecture of variation in chromatin accessibility between species, and find that cis effects are more common and of greater magnitude than trans effects. Interestingly, we find that cis and trans effects at individual genes are often negatively correlated, suggesting widespread compensatory evolution to stabilize levels of chromatin accessibility. Finally, we demonstrate that the relationship between chromatin accessibility and gene expression levels is complex, and a significant proportion of differences in chromatin accessibility might be functionally benign. There are 20 samples in total. These consist of 10 FAIRE-seq samples, specifically 6 haploid samples, S. cerevisiae strain UWOPS05_217_3 replicates 1 and 2, S. cerevisiae strain DBVPG1373 replicates 1 and 2, and S. paradoxus strain CBS432 replicates 1 and 2. There are also 4 diploid hybrid samples, hybrid between S. cerevisiae strain UWOPS05_217_3 and S. paradoxus strain CBS432 replicates 1 and 2, and the hybrid between S. cerevisiae strain DBVPG1373 and S. paradoxus strain CBS432 replicates 1 and 2. There are also RNA-seq samples for each of these 10 samples.
Project description:Here we used artificial selection to assimilate a seasonal wing color phenotype from a naturally plastic population of butterflies. Using SNP association and RNAseq we mapped three genes responsible for wing color fixation, including the color pattern supergene cortex. Combined with endocrine and chromatin accessibility assays, we found that the rapid transition of wing coloration from an environmentally determined trait to a fixed, genetic trait occurred through selection on cis-regulatory alleles of genes with wing-specific functions, not by changes in environmental detection or hormone signaling.