AP BIOLOGY

Detailed explanation-1: -Hair color is determined by the amount of a pigment called melanin in hair. An abundance of one type of melanin, called eumelanin, gives people black or brown hair. An abundance of another pigment, called pheomelanin, gives people red hair.

Detailed explanation-2: -Explain your answer. The human hair color is controlled by more than one gene. In this case, hair color is a polygenic trait, which exhibits polygenic inheritance. There are individuals who inherit different combinations of alleles that are responsible for hair colors.

Detailed explanation-3: -Hair color is determined by three factors having to do with pigments: how much pigment is present, to what degree a eumelanin or phenomelanin is present and how close together the melanin (pigment) granules are. The more eumelanin a person has, the darker his hair will be.

Detailed explanation-4: -Hair type is an interesting case of something called incomplete dominance. What this means is that with hair type, if you have one of each version of the gene, you get a mix of the two or wavy hair.

Detailed explanation-5: -Strikingly blond and red hair colors (prevalence about 2% or less) appear to be autosomal recessive but the latter may have some expression in the heterozygotes. Red hair is hypostatic to brown and black. Brown hair appears to be autosomal dominant and it is closely linked to green eye color.