Question

1. Define codominance.

2. Explain how rabbits can have more than two different coat colors.
3. Discuss how environment can influence phenotype. Give one example.

Answer 1

Codominance is a form of inheritance wherein the alleles of a gene pair in a heterozygote are fully expressed. As a result, the phenotype of the offspring is a combination of the phenotype of the parents. Thus, the trait is neither dominant nor recessive.

Answer 2

1. Codominance is a phenomenon in which both alleles of a trait are expressed. This can be seen with blood type. This is, however, to be distinguished from incomplete dominance in which the traits blend to form an intermediate phenotype (e.g. red snapdragon plant and white snapdragon plant forming a pink offspring).

2. Rabbits can have more than two different coat colors because there are numerous alleles that contribute to their coat color. This phenomenon is known as multiple alleles.

3. The environment can influence phenotype by favoring individuals who have phenotypes that give them an advantage over others (e.g. longer necks in giraffes). By favoring certain individuals, those are the ones who pass their traits onto the future population more and thus making the favorable phenotypes more prevalent.