Question

What explains how the parents in a family both have the same eye color, but some of their children have a different eye color? Assume for this example that eye color is determined by a single gene.

A. One parent is homozygous dominant, and the other heterozygous for a gene that controls eye color allowing some of the children to express a different trait.

B. The parents are both homozygous dominant for a gene that controls eye color allowing some of the children to get two recessive alleles.

C.One parent is homozygous dominant, and the other homozygous recessive for a gene that controls eye color allowing some of the children to express a different trait.

D. The parents are both heterozygous for a gene that controls eye color allowing some of the children to get two recessive alleles.

Answer 1

The correct option is D. The parents are both heter0zyg0us for a gene that controls eye color allowing some of the children to get two recessive alleles.

What is complete dominance?

When the dominant allele completely masks the recessive allele, we talk about complete dominance.

This is the case of individuals that are heter0zyg0us for a particular gene and express the dominant trait. The dominant allele is hiding the expression of the recessive allele.

In the exposed example, let us assume that the alleles that code for eye color are the followings,

• E is the dominant allele and codes for the dominant color

• e is the recessive allele and codes for the recessive color

If at least one parent is h0m0zyg0us dominant for the trait, EE, the whole progeny will express the dominant trait because all of them will carry at least one dominant allele.

If both parents are heter0zyg0us Ee, some children will express the dominant trait and some other the recessive trait. This is because some of the children receive at least one dominant allele and some others only receive recessive alleles.

Cross:

Parentals) Ee   x   Ee

Gametes) E   e    E   e

Punnett square)     E     e

                       E    EE    Ee

                       e    Ee    ee

F1) Genotype

1/4 = 25% of the progeny is expected to be h0m0zyg0us dominant EE

1/2 = 50% of the progeny is expected to be heter0zyg0us Ee

1/4 = 25% of the progeny is expected to be h0m0zyg0us recessive ee

    Phenotype

3/4 = 25% of the progeny is expected to have the dominant eye color

1/4 = 25% of the progeny is expected to have the recessive eye color

The correct option is D. The parents are both heterozygous for a gene that controls eye color allowing some of the children to get two recessive alleles.

You can learn more about complete dominance at

https://brainly.com/question/1953851

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