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Abstract Detail

The evolutionary causes and consequences of dioecy across the land plants

Delph, Lynda [1].

Sexual antagonism in Silene and other dioecious angiosperms.

Sexual antagonism, or intralocus sexual conflict, occurs in organisms with separate sexes when the following two things occur: selection is in opposing directions on a trait in the two sexes, and at least some of the loci controlling the trait are expressed in both sexes. Hence, to test for sexual antagonism one needs to know likely traits that are experiencing different directions of selection, phenotypic selection gradient analyses need to be conducted, and some knowledge of the underlying genetic architecture of the traits is needed. Through a series of quantitative-genetic studies and measurements of selection in the field, my lab has uncovered sexual antagonism for specific leaf area (SLA) that is environmentally dependent, in the dioecious flowering plant, Silene latifolia. This species exhibits sexual dimorphism in many traits. That said, SLA is one of the least sexually dimorphic traits, with males having slightly thinner leaves than females. Nevertheless, in hot, dry environments males with thin leaves die, leading to a negative selection gradient on SLA. Females, on the other hand, experience weakly positive selection on SLA in the same environment. Of 5 loci known to affect SLA in males, 3 are expressed only in males, suggesting some resolution of sexual conflict; however, a high between-sex genetic correlation for this trait exists, and SLA is genetically correlated with many other traits. Overall, our results suggest that the interaction between traits experiencing sexual conflict and ecological factors can be complicated when these traits have high genetic correlations with other divergent traits that experience their own sex specific, environment-dependent selection. When ecological factors are highly variable, even sex-specific expression might be unable to resolve sexual antagonism.

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1 - Indiana University, Department of Biology, Jordan Hall, 1001 East Third Street, Bloomington, IN, 47405, USA

natural selection
sexual dimorphism
Sexual Conflict.

Presentation Type: Symposium or Colloquium Presentation
Session: SY05
Location: Jasperwood/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 4:45 PM
Number: SY05007
Abstract ID:640
Candidate for Awards:None

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