Related Experiment Video
Updated: Jul 17, 2026

Assessing Differences in Sperm Competitive Ability in Drosophila
Published on: August 22, 2013
An evolutionary cost of separate genders revealed by male-limited evolution
N G Prasad1, S Bedhomme, T Day
1Department of Biology, Queen's University at Kingston, Biosciences Complex, 116 Barrie Street, Ontario K7L 3N6, Canada. prasad@biology.queensu.ca
Abstract:
Theory predicts that intralocus sexual conflict can constrain the evolution of sexual dimorphism, preventing each sex from independently maximizing its fitness. To test this idea, we limited genome-wide gene expression to males in four replicate Drosophila melanogaster populations, removing female-specific selection. Over 25 generations, male fitness increased markedly, as sexually dimorphic traits evolved in the male direction. When male-evolved genomes were expressed in females, their fitness displayed a nearly symmetrical decrease. These results suggest that intralocus conflict strongly limits sex-specific adaptation, promoting the maintenance of genetic variation for fitness. Populations may carry a heavy genetic load as a result of selection for separate genders.
Related Concept Videos
Criticisms of the Evolutionary Perspective
Evolutionary psychology provides one explanation for these findings, suggesting...
Mate Choice
Natural Selection and Mating Preferences
Females, due to their biological roles in conception, pregnancy, and nursing, inherently...
The Y Chromosome Determines Maleness
Evolution
Around 300 million years ago, the two sex chromosomes diverged from two identical autosomal chromosomes. Over time, the Y chromosome has lost most of its genes, shrinking in size. Today,...
X-linked Traits
X-linked Traits

