Widespread cryptic variation in genetic architecture between the sexes

Area of Science:

• Evolutionary Biology
• Genetics
• Developmental Biology

Background:

• Most of the genome is shared between sexes, suggesting shared genetic architecture for most traits.
• Shared genetic architecture is often considered a constraint on the evolution of sexual dimorphism (SD).
• SD is prevalent, leading to the hypothesis that it arises from differential regulation of shared genetic architecture.

Purpose of the Study:

• To investigate how regulatory variation influences sexual dimorphism (SD).
• To explore the effects of gene knockout mutations on mouse phenotypes and their sex-specific impacts.
• To understand the genetic basis of SD and its relationship with sex-specific genetic architecture.

Main Methods:

• Studied the phenotypic effects of thousands of gene knockout mutations in mice.
• Analyzed 202 different mouse phenotypes to assess sexual dimorphism.
• Examined sex-specific phenotypic effects of gene knockouts and regulatory changes.

Main Results:

• Many mouse traits exhibit some degree of sexual dimorphism.
• A significant proportion of gene knockouts display sex-specific phenotypic effects.
• Cryptic differences in genetic architecture between sexes were identified for many traits, leading to sexually discordant effects from concordant regulatory changes.

Conclusions:

• Sexual dimorphism can arise through sex-specific genetic architecture, independent of differential regulation of shared architecture.
• Regulatory variation plays a crucial role in generating sex-specific phenotypic effects.
• This study provides an alternative mechanism for the evolution of sexual dimorphism.