Andalusian chickens are one of the hundreds of different varieties of chickens.
ID: 150945 • Letter: A
Question
Andalusian chickens are one of the hundreds of different varieties of chickens. ( Sometime, see Feathersite.com for photographs of many more varieties of Gallus gallus.) Andalusians chickens come in 3 color varieties: black, white, and blue (so-called 'blues' are actually gray). The Black Andalusians are known to be homozygous at this color locus. We’ll symbolize their genotype with: A1A1. The White Andalusian are known to be homozyogous at this color locus. We’ll symbolize their genotype with: A2A2. When a Black and White are bred, all the members of their F1 are blue. What are the genotypes of the blue chickens? a. A1A1 b. A1A2 c. A2A2 d. either of the one above
Andalusian chickens are one of the hundreds of different varieties of chickens. ( Sometime, see Feathersite.com for photographs of many more varieties of Gallus gallus.) Andalusians chickens come in 3 color varieties: black, white, and blue (so-called 'blues' are actually gray). The Black Andalusians are known to be homozygous at this color locus. We’ll symbolize their genotype with: A1A1. The White Andalusian are known to be homozyogous at this color locus. We’ll symbolize their genotype with: A2A2. When a Black and White are bred, all the members of their F1 are blue. If you crossed two Blue Andalusians what would be the predicted genotypic ratio of their F1? a. 1:1 (50% blue: 50% black) b. 1:1 (50% blue: 50% white) c. 1:2:1 (25% white: 50% blue: 25% black) d. 2:1 (75% blue: 25% black)
Andalusian chickens are one of the hundreds of different varieties of chickens. ( Sometime, see Feathersite.com for photographs of many more varieties of Gallus gallus.) Andalusians chickens come in 3 color varieties: black, white, and blue (so-called 'blues' are actually gray). The Black Andalusians are known to be homozygous at this color locus. We’ll symbolize their genotype with: A1A1. The White Andalusian are known to be homozyogous at this color locus. We’ll symbolize their genotype with: A2A2. When a Black and White are bred, all the members of their F1 are blue. What would be the predicted phenotypic ratio? a. 1:1 (50% blue: 50% black) b. 1:1 (50% blue: 50% white) c. 1:2:1 (25% white: 50% blue: 25% black) d. 2:1 (75% blue: 25% black)
Explanation / Answer
c. 1:2:1 (25% white: 50% blue: 25% black)
This ratio is obtained as follows-
Black A1A1 X white A2A2,
A1A2- 100% BLUE
A1A2 X A1A2(selfing)
A1A1 - Black(1)
A1A2- BLUE(2)
A2A2- white(1)
Ratio - 1:2:1 (25% white: 50% blue: 25% black)
A1 A1 A2 A1A2 A1A2 A2 A1A2 A1A2