AP BIOLOGY

Detailed explanation-1: -A dominant allele is an allele that is expressed in the phenotype of an individual even when present as a single copy. This allele is not affected nor masked by the presence of the other allele.

Detailed explanation-2: -Dominant alleles are always expressed if present in the genotype. This can occur either with two dominant alleles (homozygous dominant) or one dominant allele and one recessive allele (heterozygous).

Detailed explanation-3: -Genes come in different versions, or alleles, with dominant alleles being expressed over recessive alleles. Recessive alleles are only expressed when no dominant allele is present. In most sexually reproducing organisms, each individual has two alleles for each gene (one from each parent).

Detailed explanation-4: -If both alleles are dominant, it is called codominance?. The resulting characteristic is due to both alleles being expressed equally. An example of this is the blood group AB which is the result of codominance of the A and B dominant alleles.

Detailed explanation-5: -Both copies of the gene can contribute to an individual’s phenotype. Dominant alleles will produce the phenotype associated with them, even in the presence of another allele.