MIT Biology Department 7.012: Introductory Biology - Fall 2004 Instructors: Professor Eric Lander, Professor Robert A. Weinberg, Dr. Claudette Gardel 7.012 Genetics Section Problems For each set of data below, determine the genotype of the parents in cross 1. Where it applies, indicate which phenotypes are dominant and which are recessive. Mice I a) cross 1: red-eyed mouse ____________ X white-eyed mouse ____________ gives F1: all red-eyed cross 2: red-eyed F1 X red-eyed F1 gives F2: 36 red-eyed 13 white-eyed b) cross 1: long-eared mouse ____________ X short-eared mouse ____________ gives F1: 12 long-eared 10 short-eared cross 2: long-eared F1 X long-eared F1 gives F2: 36 long-eared 13 short-eared Flowers cross 1: blue-flowered plant ____________ X white-flowered plant ____________ gives F1: all pale-blue-flowered cross 2: pale-blue F1 X pale-blue F1 gives F2: 27 blue 49 pale-blue 24 white Blood Type a) cross 1: person, type A blood ____________ X person with type B ____________ gives F1: all type AB blood cross 2: type AB F1 X type AB F1 gives F2: 2 type A 4 type AB 1 type BBlood Type, continued b) cross 1: type A blood ____________ X type B ____________ gives F1: 2 type A blood 3 type AB blood 1 type B blood 2 type O blood Mice II a) cross 1: tail-less mouse ____________ X normal mouse ____________ gives F1: 10 tail-less 9 normal cross 2: tail-less F1 X tail-less F1 gives F2: 10 normal 21 tail-less 9 dead b) cross 1: blue-eyed, long-toothed mouse X brown-eyed, short-toothed mouse ____________ X ____________ gives F1: all blue-eyed, short-toothed cross 2: blue-eyed, short-toothed F1 X blue-eyed, short-toothed F1 gives F2: 92 31 29 9 blue-eyed short-toothed blue-eyed long-toothedbrown-eyed short-toothed brown-eyed long-toothed Plants cross 1: tall, green plant ____________ X short, yellow plant ____________ gives F1: 20 tall green 20 short green cross 2: tall, green X short, yellow (different plants than (b)) gives F1: 19 tall green 21 tall
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