A restriction-fragment length polymorphism at a site in the X chromosome has three alleles, A₁, A₂, and A₃. The gel below is the DNA fingerprint for two prospective parents (Mo and Fa) along with DNA types that might (or might not) correspond to their offspring. What are the possible phenotypes of daughters from this mating?

Question

Quizplus · Accepted Answer

By examining the gel, we can see that the mother (Mo) is heterozygous for the allele, with one band appearing at approximately 240 bp and one band appearing at approximately 250 bp. The father (Fa) appears to be homozygous for the allele with one band at approximately 250 bp. Therefore, the only possible combinations or phenotypes for daughters from this mating would be: A₁/A₂ (H) or A₂/A₃ (L). Thus, the answer is D, as these are the only two possible phenotypes for daughters from this mating.

A Restriction-Fragment Length Polymorphism at a Site in the X