What color are a persons eyes if they have no gene for pigment color?
Although some human traits are controlled by a single gene, most human characteristics are controlled by several genes. Polygenic traits are controled by two or more genes. Skin and eye color are both influenced by the additive effects of from three to six genes. Each of these genes results in the formation of a certain amount of a pigment called melanin. The more of the genes that are expressed, the darker the color produced. End Of Instruction practice test question #39 Multiple-allele traits are controlled by three or more alleles of the same gene. Human blood type is an example. There are three forms of the blood type gene, IA, IB, and i. An individual’s blood type is determined by two of the three genes. Blood Type Rh Type How Many Have It Percentage O + 1 person in 3 37.4% 44% O – 1 person in 15 6.6% A + 1 person in 3 35.7% 42% A – 1 person in 16 6.3% B + 1 person in 12 8.5% 10% B – 1 person in 67 1.5% AB + 1 person in 29 3.4% 4% AB – 1 person in 167 .6% Sex-linked traits have ge
