Immunogenic males: a genome-wide analysis of reproduction and the cost of mating in Drosophila melanogaster females
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ABSTRACT: 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.
ORGANISM(S): Drosophila melanogaster
SUBMITTER: Paolo Innocenti
PROVIDER: E-GEOD-12834 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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