Question

In chickens, the creeper phenotype is characterized by shortened legs and wings. Affected chickens cannot walk normally and have to creep along. Creeper chickens are heterozygous for he creeper allele, C. In the homozygous state, C disrupts embryological development and lead to death of the chicken before hatching

a. What are the expected genotypic and phenotypic ratios from the cross of two creeper chickens?

b. Is the creeper allele dominant or recessive for leg shape? Explain.

C. Is the creeper allele dominant or recessive for lethality? Explain.

Answer 1

A. the ratio obtained is 2/3 creeper and 1/3 normal because homozygous creeper chiken die before hatching.

B. Creeper allele is dominant for the leg shape because in heterozygous condition having one creeper allele and one normal allele, the chiken shows stunted and short leg phenotype.

C. Creeper allele is recessive for the the lethality because heterozygous chicken with one creeper allele and one normal allele doesn't show the lethality and survive with short and stunted legs. But in case having both creeper allele the chiken dies due to lethality.

This shows that creeper allele is dominant for leg shape and recessive for the lethality