Question

You just bought two black guinea pigs, one male and one female, of the same genotype from the pet store that are known to be heterozygous (Bb). You also know that black fur (BB) is dominant over white fur (bb) and that a lethal recessive allele is located only one cM away from the recessive b allele, and your animals are both heterozygous for this gene also. What is the probability of finding a white individual among the progeny if you cross these two animals?

Answer 1

Answer: The probability of finding a white individual among the progeny if you cross these two animals is ¼.

Step-by-step explanation: Since these two animals are heterozygous black animals (Bb), crossing Bb x Bb will produce offsprings that are black (¾) and white (¼).

The first B will meet with the second B to form a BB (Black) progeny.

The first B will meet with the second b to form Bb (Black) progeny.

Likewise, the first b will meet with the first B to form Bb (Black) progeny.

Lastly, the first b will meet with the second b to form bb (white) progeny.

These are the possible progeny from the cross between Bb and Bb. Therefore, the probability of having white offspring is ¼.