Hair color is due to the presence of melanin. There are two types of melanin produced by melanocytes. One is eumelanin, which is responsible for black (homozygous), brown (heterozygous), and blond (recessive) hair colors. The other is pheomelanin, which is responsible for red hair color. During melanin synthesis, MCR1gene converts pheomelanin to eumelanin. However, a variant of the MCR1 gene (MCR1variant), prevents this conversion. A cross between a blond-haired mother and a red-haired father produced 100% brown-haired children. When they came of age, one child married a double heterozygote, and both were blessed with 7 children; 2 with black hair, 2 with brown hair, 1 with blond hair, and 2 with red hair. TIP: Black hair is homozygous while brown hair is heterozygous, thus represented together in determining the ratio and written as black/brown in the 9:3:3:1 ratio. However, all F2s must be given their COMPLETE genotypes. Using the 7-step method, determine the genotypes of the P1, the F1, and the F2s. BOX your answers
Hair color is due to the presence of melanin. There are two types of melanin produced by melanocytes. One is eumelanin, which is responsible for black (homozygous), brown (heterozygous), and blond (recessive) hair colors. The other is pheomelanin, which is responsible for red hair color. During melanin synthesis, MCR1gene converts pheomelanin to eumelanin. However, a variant of the MCR1 gene (MCR1variant), prevents this conversion.
A cross between a blond-haired mother and a red-haired father produced 100% brown-haired children. When they came of age, one child married a double heterozygote, and both were blessed with 7 children; 2 with black hair, 2 with brown hair, 1 with blond hair, and 2 with red hair.
TIP: Black hair is homozygous while brown hair is heterozygous, thus represented together in determining the ratio and written as black/brown in the 9:3:3:1 ratio. However, all F2s must be given their COMPLETE genotypes.
Using the 7-step method, determine the genotypes of the P1, the F1, and the F2s. BOX your answers
Trending now
This is a popular solution!
Step by step
Solved in 2 steps
