Question

In 1981, a stray black cat with unusual rounded, curled-black ears was adopted by a family in California. Hundreds of descendants of the cat have since been born, and cat fanciers hope to develop a true–breeding variety. How would you determine whether the curl allele is dominant or recessive? How would you obtain true-breeding curl cats? How could you be sure they are true-breeding?

Short answer

The curl allele is a dominant condition confirmed by crossing the stray cat with curled feature with the non-curled cat.

True breeding curl cat is obtained by the breeding of the curled cat with another curled cat.

True breeding is confirmed by crossing the homozygous individual with the heterozygous individual.

Step-by-step solution

Determination of dominant or recessive condition in the curl allele 

The mating of the stray cat with the non curled cat proves that the curled ear is the dominant feature in some of the rings. The non curled cats are the offspring produced in the recessive condition.

True breeding curl cats

True breeding is the breeding in which the same type of offspring is produced.

The crossing of curled cats with another curled cat results in the true-breeding condition. True breeding forms the offspring with curled features.

Confirmation of true breeding condition

Curl cat is homozygous recessive in the case of the trait with the recessive condition. Homozygous traits have two copies of a single allele.

In the case of the dominant condition, the test cross is carried with the heterozygous individual with the homozygous recessive trait.