Question

An important gene carried on the X chromosomes is responsible for normal color vision, which is produced by the dominant allele. What does the recessive allele produce?
A. amnesia
B. colorblindness
C. blindness
D. hearing impairments

Answer 1

A dominant allele of a gene appears dominant because it produces an enzyme that takes a precursor and converts it to an end product. A recessive allele appears as a recessive because the gene produces an enzyme that fails to convert a precursor to an end product.

If so,For example, if a person has one gene for blue eyes and one for brown, that person will always have brown eyes because they are the dominant trait. For a person to have blue eyes, both their genes must be blue (recessive). When a person has two dominant alleles, they are referred to as homozygous dominant. If they have one dominant allele and one recessive allele, they are referred to as heterozygous.

Usually, this masking effect is done by virtue of the fact that the recessive gene has a loss of some function that the dominant gene has. For example, in the case of ABO blood types, the O type is recessive because it does not produce any antigens or antibodies, whereas A and B types (which are codominant) do. Or, in the above case dealing with eye color, there is a complete loss of pigment in blue-eyed people, therefore to express the phenotype, both copies of the gene (after all, humans are diploid) must have that same loss of function.....