Sexual dimorphism

IMPC data demonstrates the effect of sex on many phenotypes, supporting the importance of including males and females in biomedical research

Sexual dimorphism in 14,250 wildtype mice

The impact of sex on phenotypes of wild-type C57BL/6N mice measured using the IMPC adult phenotype pipeline at ten global research centers.

Sex effect (5% FDR) was detected in:

  • 9.9% categorical phenotypes (545 examined, e.g. abnormal corneal opacity)
  • 56.6% continuous phenotypes (903 examined, e.g. blood glucose levels)

Sexual dimorphism in 2,186 knockout mouse strains

The impact of sex on phenotypes of knockout C57BL/6N mouse lines measured using the IMPC adult phenotype pipeline at ten global research centers. Only strains with an abnormal phenotype attributable to the knockout allele (i.e genotype effect) were included.

Sex modified the genotype effect on mutant phenotypes in:

  • 13.3% categorical phenotypes (1,220 examined; 20%FDR)
  • 17.7% continuous phenotypes (7,929 examined; 5% FDR)


In 2017, the IMPC analysed phenotype data collected over a 5 year period from 14,250 wildtype and 40,192 mutant mice representing 2,186 knockout lines.

  • Weight was included as a covariate in the continuous data set analyses, as body size is dimorphic between male and female mice and many continuous traits correlate with body weight.
  • For wild-type mice, males and females within a center were compared
  • For the mutant mice, lines were selected (1) if there was an abnormal phenotype associated with the knockout allele (2) if significant, whether sex influenced the phenotype.

The wild-type analysis is from the original manuscript. The mutant line analysis is updated with each IMPC data release


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