Sexual dimorphism in trait variability and its eco-evolutionary and statistical implications

Biomedical and clinical sciences are experiencing a renewed interest in the fact that males and females differ in many anatomic, physiological, and behavioural traits. Sex differences in trait variability, however, are yet to receive similar recognition. In medical science, mammalian females are assumed to have higher trait variability due to estrous cycles (the ‘estrus-mediated variability hypothesis’); historically in biomedical research, females have been excluded for this reason. Contrastingly, evolutionary theory and associated data support the ‘greater male variability hypothesis’. Here, we test these competing hypotheses in 218 traits measured in >26,900 mice, using meta-analysis methods. Neither hypothesis could universally explain patterns in trait variability. Sex bias in variability was trait-dependent. While greater male variability was found in morphological traits, females were much more variable in immunological traits. Sex-specific variability has eco-evolutionary ramifications, including sex-dependent responses to climate change, as well as statistical implications including power analysis considering sex difference in variance.Read more…

Biomedical and clinical sciences are experiencing a renewed interest in the fact that males and females differ in many anatomic, physiological, and behavioural traits. Sex differences in trait variability, however, are yet to receive similar recognition. In medical science, mammalian females are assumed to have higher trait variability due to estrous cycles (the ‘estrus-mediated variability hypothesis’); historically in biomedical research, females have been excluded for this reason. Contrastingly, evolutionary theory and associated data support the ‘greater male variability hypothesis’. Here, we test these competing hypotheses in 218 traits measured in >26,900 mice, using meta-analysis methods. Neither hypothesis could universally explain patterns in trait variability. Sex bias in variability was trait-dependent. While greater male variability was found in morphological traits, females were much more variable in immunological traits. Sex-specific variability has eco-evolutionary ramifications, including sex-dependent responses to climate change, as well as statistical implications including power analysis considering sex difference in variance.Read more…


Type Path Last modified Size Actions
.gitignore 3 days, 17 hours ago 186.0B
CreatingFilesForShinyApp.R 3 days, 17 hours ago 844.0B
LICENSE 3 days, 17 hours ago 1.0KiB
MouseSexDiffVar_Oct_2020.html 3 days, 17 hours ago 3.8MiB
Prep & old 3 days, 17 hours ago 13.0MiB
R 3 days, 17 hours ago 11.2KiB
README.md 3 days, 17 hours ago 2.9KiB
SexDifference_Shiny 3 days, 17 hours ago 762.8KiB
data 3 days, 17 hours ago 10.1KiB
executableMS 3 days, 17 hours ago 2.5MiB
export 3 days, 17 hours ago 33.1MiB
images 3 days, 17 hours ago 974.9KiB
mice_sex_diff.Rproj 3 days, 17 hours ago 204.0B
results 3 days, 17 hours ago 74.0KiB
scripts 3 days, 17 hours ago 413.0KiB