Question

In mice, the ability to run normally is a dominant trait. Mice with this trait are called running mice (R). The recessive trait causes mice to run in circles only. Mice with this trait are called waltzing mice (r). Hair color is also inherited in mice. Black hair (B) is dominant over brown hair (b). Cross a heterozygous running, heterozygous black mouse with a homozygous circling brown mice to see what percentage of the offspring will be circling running and brown?

Answer 1

When a heterozygous running mouse (Rr) is crossed with a homozygous circling brown mouse (rrbb), approximately 25% of the offspring will be circling running and brown.

Step-by-step explanation:

To determine the percentage of offspring that will be circling running and brown, we need to consider the inheritance of two traits: the ability to run normally and hair color. In this case, running normally (R) is a dominant trait, and running in circles (r) is recessive. Black hair (B) is dominant over brown hair (b).

When we cross a heterozygous running mouse (Rr) with a homozygous circling brown mouse (rrbb), we can use Punnett squares to visually represent the possible genotypes and phenotypes of the offspring.

The potential genotypes of the offspring will be: RrBb, Rrbb, rrBb, and rrbb. After crossing the parental genotypes, we see that 25% of the offspring will be circling running and brown (rrbb). Therefore, the percentage of the offspring that will be circling running and brown is 25%.