Related Experiment Video
Updated: Aug 7, 2026

Gene-environment Interaction Models to Unmask Susceptibility Mechanisms in Parkinson's Disease
Published on: January 7, 2014
Genotype modulates testosterone-dependent activity and reactivity in male mice
Abstract:
Adult castration significantly reduced the homecage locomotor activity of both inbred C57BL/6J and DBA/2J and outbred Rockland-Swiss (R-S) male mice. Castrated C57BL animals exhibited greater reductions in this behavior than did the other genotypes. Locomotor activity in a novel environment (reactivity) was also reduced by castration but only for inbred males. In both test situations, postcastration reductions in ambulation were prevented by implants of testosterone (T)-containing Silastic capsules. Thus, testicular hormones promote activity and reactivity in the male mouse in a genotype-dependent fashion.
Related Concept Videos
In-vitro Mutagenesis
Background and Environment Affect Phenotype
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
The Y Chromosome Determines Maleness
Evolution
Around 300 million years ago, the two sex chromosomes diverged from two identical autosomal chromosomes. Over time, the Y chromosome has lost most of its genes, shrinking in size. Today,...
Dosage Compensation
In addition to sexual development, the X chromosome has genes involved in autosomal functions such as brain development and the immune system. Therefore, males and females with distinct numbers of X chromosomes will have...

