You identify an RFLP in mice by digesting genomic DNA with HindIII enzyme and radiolabeling a piece of probe DNA.Southern blot analysis shows that the probe detects a 2-kb fragment in one strain of mice and a 4-kb fragment in another strain of mice.The two mice strains are crossed to produce an F₁ generation.Two F₁ siblings are mated to produce a dozen F₂ progeny.You isolate genomic DNA from several F₁ and F₂ individuals, digest with HindIII, and perform a Southern blot with the same probe. How many bands would be seen in the Southern blot of an F₂ individual?

Question

Quizplus · Accepted Answer

The F₂ generation, being the offspring of two F₁ siblings, would inherit a combination of the 2-kb and 4-kb fragments from their parents. This means that an individual could have either two 2-kb fragments, two 4-kb fragments, or one of each, leading to the possibility of seeing 1 (if both fragments are the same size), 2 (if they inherit one of each size), or 3 bands (if heterozygous at two loci, showing both parental and recombinant bands). Therefore, two of the answers are possible depending on the specific inheritance of the fragments.

You Identify an RFLP in Mice by Digesting Genomic DNA