1. You are mapping cardinal traits. You know that having angular feathers on top
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1. You are mapping cardinal traits. You know that having angular feathers on top of the head (A) is dominant to flat feathers (aa), black coloration around the beak and eyes (B_) is dominant to gray coloration, and colorful plumage (C_) is dominant to drab/less colorful plumage (cc). You cross a true male that has angular feathers, black around the beak, and colorful plumage with a true breeding female that has flat feathers, gray around the less colorful plumage. All of the F1 offspring have angular feathers, black around the beak, and colorful plumage. You then testcross a female F1. Given the offspring phenotypes and counts below, map the traits. (7pts) beak, and a. Which locus is in the middle? (circle one) A ffeel free to show your work below) Phenotype Counts angular, black, colorful 72 flat, gray, drab angular, gray, drab flat, black, colorful angular, black, drab flat, gray, colorful angular, gray, colorful 68 101 95 331 326 b. What is the distance between locus A and B? (feel free to show your work below c. What is the distance between locus A and C? ffeel free to show your work below) flat, black, drab d. What is the distance between locus B and C? ffeel free to show your work below) e. Draw the two chromosomes in the correct configuration and distance between the loci. f. Calculate interference. 96. A cross-over at one region suppresses adjacent cross-over events by (feel free to show your work below)Explanation / Answer
a) The gene order is B A C. A is in middle.
b) DCO - gray, angular, colorful = 4 and black, flat, drab =3
SCO B-A = Black, flat, colorful = 95 and gray, angular, drab = 101
Distance between locus B and A = (95+101+4+3) *100 / Total progeny
Distance between locus B and A = 203*100 / 1000 = 20.3 mu
c) Distance between locus A and C = (72+68+4+3) *100/1000 = 14.7 mu
d) Distance between B and C = 20.3 + 14.7 = 35 mu
f) interference = 1- (observed DCO/expected DCO)
interference = 1- (4+3)/(0.203) (0.147) (1000) = 0.76
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