In loppins (fictitious diploid invertebrates),ear shape is controlled by two genes with two alleles each;upright ears (F)is dominant to floppy ears (f),and double-pointed ears (P)is dominant to single-pointed ears (p).Moreover,due to genetic interactions,floppy ears are always single-pointed.A loppin with floppy ears is crossed to a loppin with upright single-pointed ears,and the phenotypic ratios in the offspring are 2 floppy : 1 double-pointed upright : 1 single-pointed upright.What are the genotypes of the parents?

Question

Quizplus · Accepted Answer

The phenotypic ratios in the offspring of 2 floppy : 1 double-pointed upright : 1 single-pointed upright suggest that the parents are heterozygous for both genes. Only choice C (P/p;f/f and p/p;F/f) fits this requirement. The first parent is heterozygous for the ear shape gene (F/f) and homozygous recessive for the ear point gene (p/p). The second parent is homozygous dominant for the ear point gene (F/F) and heterozygous for the ear shape gene (F/f). When these parents produce offspring, the possible combinations of alleles that result in each phenotype are:
- 2 floppy: f/p x f/p
- 1 double-pointed upright: F/P x f/p, F/p x P/f, f/P x P/f
- 1 single-pointed upright: F/p x f/p, f/p x F/f
These ratios match the ones observed in the offspring, confirming that choice C is the correct answer.

In Loppins (Fictitious Diploid Invertebrates),ear Shape Is Controlled by Two