Positive selection and relaxed purifying selection contribute to rapid evolution of sex-biased genes in green seaweed Ulva.

ABSTRACT:

Background

The evolution of differences in gamete size and number between sexes is a cornerstone of sexual selection theories. The green macroalga Ulva, with incipient anisogamy and parthenogenetic gametes, provides a unique system to investigate theoretical predictions regarding the evolutionary pressures that drive the transition from isogamy to anisogamy, particularly in relation to gamete size differentiation and sexual selection. Its minimal gamete dimorphism and facultative parthenogenesis enable a rare window into early evolutionary steps toward anisogamy.

Results

By analyzing the expression profiles of sex-biased genes (SBGs) during gametogenesis, we found that SBGs evolve faster than unbiased genes, driven by higher rates of non-synonymous substitution (dN), indicat

SUBMITTER: Liu X 

PROVIDER: S-EPMC12063405 | biostudies-literature | 2025 May

REPOSITORIES: biostudies-literature