Effect of the Tfm mutation on handedness in mice.

The hyposthesis has been proposed that testosterone is involved in the determination of handedness in man: a high sensitivity to testosterone being associated with left handedness. Handedness in mice is tested according to Collins' paradigm: most mice present either a right or a left paw preference but others are ambilateral. The hypothesis that there is an association between a low neonatal imprinting by testosterone and a strong handedness (right or left) is tested here using Tfm male mice which are testosterone insensitive. Our results confirmed the hypothesis, since Tfm males were as well lateralized as their female siblings and significantly more strongly lateralized than their male siblings not carrying the mutation.