Abstracts (first author)

Talk 

Effects of experimental mating system variation on transcriptome evolution and mating response in female Drosophila pseudoobscura

Author(s): Immonen E, Snook RR, Ritchie MG

Summary:

Interactions between the sexes are believed to be a potent source of selection on sex-specific evolution, but the way in which sexual interactions influence females at the molecular level is poorly understood. We examined the effects of 100 generations of elevated polyandry and enforced monandry on gene expression evolution in female Drosophila pseudoobscura. We assessed differences in gene expression between females from the two selection regimes and how the expression response to mating depended on female sexual selection history, indirect genetic effects (IGEs) due to the genotype of the male and female-by-male genotype interactions. Our data show large-scale gene expression divergence between the experimentally evolved females, with selection mainly targeting female-biased genes expressed in the ovaries. Most of the expression differences were un-affected by mating, however we also observed substantial differences in the expression response to mating between the experimental females. The indirect genetic effects of the male selection history on the female gene expression response were surprisingly small. Our results provide critical experimental evidence for a role of female-specific selection arising from polyandry in promoting rapid evolution of the female transcriptome.



Abstracts (coauthor)

Summary:

Although it is well known that mating increases the risk of infection, we do not know whether females have adaptive responses to mitigate the fitness costs of sexually transmitted infections (STIs). The major problem has been that we lack a suitable model host/pathogen system for studying the costs of STIs. Recently, Turandot-M (TotM), a member of the Turandot family of genes involved in immune and stress response, has been shown to be upregulated in female Drosophila melanogaster when they hear male courtship songs. Here we use the Gal4/UAS RNAi gene knockdown system to test whether TotM provides survival and fecundity benefits for females that mate with fungus-infected males. We show that when the fungus, Metarhizium robertsii, is sexually transmitted it reduces female reproductive output across all fly lines. By comparing the knockdown line (Gal4/UAS-TotM) with control lines (Gal4/+ and UAS-TotM/+), we found that TotM provides a survival benefit for females infected with an STI and a survival cost for healthy females. Interestingly, TotM does not provide a benefit for females under direct topical infection with M. robertsii. Together these results show that TotM plays a previously-overlooked role in defence against STIs and it suggests that females use auditory cues to anticipate the immune challenges that come with mating.

Contacts

Chairman: Octávio S. Paulo
Tel: 00 351 217500614 direct
Tel: 00 351 217500000 ext22359
Fax: 00 351 217500028
email: mail@eseb2013.com

Address

XIV Congress of the European Society for Evolutionary Biology

Organization Team
Department of Animal Biology (DBA)
Faculty of Sciences of the University of Lisbon
P-1749-016 Lisbon
Portugal

Website

Computational Biology & Population Genomics Group 
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