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?

Question

Quizplus · Accepted Answer

The probability of obtaining a white (bb) guinea pig from two heterozygous (Bb) parents is 1/4 or 0.25 under simple Mendelian inheritance. However, because the lethal recessive allele is closely linked to the b allele (1 cM or 1% recombination frequency), the actual probability of a bb offspring surviving is reduced. The calculation for a surviving white (bb) individual takes into account the recombination frequency: 0.25 (chance of bb) * 0.99 (chance of not inheriting the lethal allele due to recombination) = 0.2475 or 0.004975 when expressed as a proportion of all possible outcomes, including those affected by the lethal allele.

You Just Bought Two Black Guinea Pigs, One Male and One