Distinguish between the terms "dominance" and "recessiveness" and between "heterozygous" and "homozygous," using the trait of unattached versus attached earlobes.

Question

What will be an ideal response?

Answer 1

Dominant alleles are ones that result in a specific phenotype, even if only one copy of the allele is inherited, while recessive alleles only result in a specific phenotype if a dominant allele is not also present. Heterozygous means that two different alleles of a gene are present, while homozygous means that just one allele of a gene is present. Unattached earlobes are controlled by a dominant allele, while attached earlobes are controlled by a recessive allele. This means that a person will show the phenotype of unattached earlobes either when they are homozygous for the dominant allele or when they are heterozygous and have one dominant and one recessive allele. Attached earlobes are controlled by the recessive allele, so a person will only exhibit attached earlobes if they inherit two recessive alleles and thus have a homozygous genotype for earlobe attachment.