Cite the most common molecular explanations for dominant and recessive alleles.

Dominant allele codes for a functional protein. Recessive allele codes for a less functional or nonfunctional protein, or it does not code for any protein.

Explanation:

Alleles are different forms of a gene. There are two types, dominant and recessive allele. Heterozygous organisms have one of each, and the dominant allele is expressed. Homozygous organisms have either two dominant alleles or two recessive alleles.

A dominant allele produces a functional protein, even in the presence of a recessive allele, because only one copy of the allele is enough and it masks the effects of the recessive allele. This dominant trait is shown in individuals who are homozygous dominant or heterozygous,

A recessive allele produces a less functional or nonfunctional protein, or it does not code for any protein at all. A recessive allele does not become a trait unless both copies of the gene are present.