Eye color in humans. Two gene loci. The mating of two people with light brown eyes can lead to children with five possible eye colors . AaBb X AaBb 2. Polygenic traits controlled by three or more genes.
Many human disorders follow Medalian patterns of inheritance.
Recessively inherited disorders. Most common inherited disease among African Americans. Caused by a single amino acid substitution in hemoglobin. B. Dominant inherited disorders. Slow, progressive deterioration of parts of the brain.