AP BIOLOGY

Detailed explanation-1: -Hh is an example of a heterozygous gene. A heterozygous gene is a gene that carries two different alleles and can be represented by a small letter and a big letter (Hh or hH).

Detailed explanation-2: -Patients who test as type O may have the Bombay phenotype if they have inherited two recessive alleles of the H gene, (their blood group is Oh and their genotype is “hh"), and so do not produce the “H” carbohydrate (fucose) that is the precursor to the “A” and “B” antigens.

Detailed explanation-3: -An individual with one altered and one unaltered copy of the gene is known as a carrier of HH. Carriers generally do not accumulate enough iron to cause any tissue damage. As HH is genetic, the family members of an individual with HH are at risk of being carriers or being affected themselves.

Detailed explanation-4: -A homozygous genotype contains two identical alleles. An individual can either be homozygous dominant (ex: HH) or homozygous recessive (ex: hh). A heterozygous genotype contains two different alleles (ex: Hh).