Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

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Female Drosophila melanogaster gene expression and mate choice: candidate genes underlying sexual isolation

ABSTRACT: 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.

ORGANISM(S): Drosophila melanogaster

SUBMITTER: Richard Bailey

PROVIDER: E-GEOD-27076 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Female Drosophila melanogaster gene expression and mate choice: the X chromosome harbours candidate genes underlying sexual isolation.

Bailey Richard I RI Innocenti Paolo P Morrow Edward H EH Friberg Urban U Qvarnström Anna A

PloS one 20110228 2

<h4>Background</h4>The evolution of female choice mechanisms favouring males of their own kind is considered a 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.<h4>Methods and findings</h4>We used mate choice experiments and gene expression analysis of female Drosophila melanogaster to examine three key ...[more]

PMID: 21386982

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Project description:In Drosophila melanogaster, mating radically transforms female physiology and behavior. Post-mating responses include an increase in the oviposition rate, a reduction in female receptivity, and an activation of the immune system . The fitness consequences of mating are similarly dramatic – females must mate once in order to produce fertile eggs, but additional matings have a clear negative effect. Previously, microarrays have been used to examine gene expression of females differing in their reproductive status with the aim of identifying genes influenced by mating. However, since only virgin and single mated females were compared, transcriptional changes associated with reproduction (under natural selection) and the effects of male-induced harm (under sexually antagonistic selection) cannot be disentangled. We partitioned these fundamentally different effects by instead examining the expression profiles of virgin, single mated and double mated females. We found substantial effects relating to reproduction and further effects that are only attributable to a second mating. Immune response genes dominate this male-induced harm effect indicating that the cost of mating may be due partly to this system's activation. We propose that both sexually antagonistic and natural selection have been important in the evolution of the innate immunity genes, thereby contributing to the sexual dimorphismand rapid evolution at these loci. Keywords: Female response to mating Female flies were flash frozen in liquid nitrogen either as virgins or 6 hours after mating and stored at -80°C until RNA extraction was performed (not more than 2 days). 8 whole flies – randomly selected within each treatment – were pooled for each extraction. Total RNA was extracted using Trizol (Invitrogen) and purified with an RNeasy Mini Kit (Qiagen). RNA quantity and quality was checked with an Agilent Bioanalyzer. According to the manufacturer's instructions, samples were prepared and hybridized to Affymetrix GeneChip Drosophila Genome 2.0 (Affymetrix, Santa Clara, CA, USA) by the Uppsala Array Platform (Uppsala, Sweden). Each experimental treatment consisted of 4 independent RNA extractions and hybridizations, giving a total of 12 arrays.

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Dataset Information

Female Drosophila melanogaster gene expression and mate choice: candidate genes underlying sexual isolation

Publications

Female Drosophila melanogaster gene expression and mate choice: the X chromosome harbours candidate genes underlying sexual isolation.

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