Question

You have available a dwarf male mouse with the genotype Igf2- Igf2-and a dwarf female with the genotype Igf2- Igf2. What is the minimum number of generations it would take to produce a normal male? Hint: mice inbreed happily.

Answer 1

To produce a normal-sized mouse from two dwarf parents homozygous for the recessive dwarf allele, it would take a minimum of two generations, introducing a heterozygous normal-sized mouse into the breeding process.

Step-by-step explanation:

The question pertains to Mendelian genetics, specifically to the inheritance patterns of dwarfism in mice, which is determined by alleles at the Igf2 gene locus. Since both parents are homozygous recessive for the dwarf allele (Igf2-), the minimum number of generations required to produce a normal-sized mouse, assuming a normal-sized allele (Igf2+) is dominant, would be two. Initially, a heterozygous normal-sized mouse needs to be introduced to the breeding population. The first generation (F1) will all be dwarfs (Igf2-), but they would be carriers of the Igf2+ allele. By intercrossing the F1 generation or backcrossing with a normal-sized mouse, the second generation (F2) has a chance of producing a normal-sized mouse if the Igf2+ allele is indeed dominant and follows simple Mendelian inheritance patterns.