Selective Breeding for a Behavioral Trait Changes Digit Ratio
2008

Selective Breeding Changes Mouse Digit Ratio

Sample size: 1013 publication 10 minutes Evidence: moderate

Author Information

Author(s): Yan Reginia H. Y., Malisch Jessica L., Hannon Robert M., Hurd Peter L., Garland Theodore Jr

Primary Institution: University of Alberta, University of California Riverside

Hypothesis

If digit ratio reflects the organizational effects of testosterone, then we would find a consistent sex difference in the mice.

Conclusion

Selective breeding for high voluntary exercise in mice increased the 2D:4D digit ratio, suggesting a 'feminization' effect contrary to human studies.

Supporting Evidence

  • Mice from the selected lines showed higher 2D:4D ratios than control lines.
  • Females had higher 2D:4D ratios than males in the selected lines.
  • The study suggests that digit ratio may reflect glucocorticoid effects rather than just testosterone.

Takeaway

The study found that breeding mice for exercise made their finger ratios more like those of females, which is different from what we see in humans.

Methodology

Mice were selectively bred for high rates of voluntary exercise, and their digit ratios were measured and compared to control lines.

Limitations

The study may not directly correlate mouse behavior with human behavior due to differences in physical fitness measures.

Participant Demographics

Mice from selected (High Runner) and control lines were used in the study.

Statistical Information

P-Value

p=0.0115 for sex difference in selected lines

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1371/journal.pone.0003216

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