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Title: If you cross one fly that is heterozygous for both traits with a fly that is heterozygous for red eyes? Post by: Fire_Fly on Sep 25, 2012 In fruit flies, red eyes (R) are dominant to maroon (r) eyes, and brown bodies (B) are dominant to tan bodies (b). You cross one fly that is heterozygous for both traits with a fly that is heterozygous for red eyes and homozygous for tan bodies.
What fraction of the offspring will have red eyes and brown bodies? What fraction of the offspring will have maroon eyes and brown bodies? What fraction of the offspring will have red eyes and tan bodies? What fraction of the offspring will have maroon eyes and tan bodies? Title: If you cross one fly that is heterozygous for both traits with a fly that is heterozygous for red eyes? Post by: Julaaro on Sep 25, 2012 The question asks for cross between, "heterozygous for both traits with a fly that is heterozygous for red eyes and homozygous for tan bodies" which means -
RrBb x Rrbb Now gamates from the first parent will be RB, rB, Rb and rb. Gamates from second parent will be Rb and rb. Now making a crossing square. So, the cross will result in 8 progenies namely. RRBb, RrBb, RRbb, Rrbb, RrBb, rrBb, Rrbb, and rrbb. What fraction of the offspring will have red eyes and brown bodies? > There are 3 offsprings with red eyes and brown bodies, so fraction = 3/8 What fraction of the offspring will have maroon eyes and brown bodies? > There is one progeny with maroon eyes and brown bodies, so fraction = 1/8 What fraction of the offspring will have red eyes and tan bodies? > There are 3 progenies with red eyes and tan bodies, so fraction = 3/8 What fraction of the offspring will have maroon eyes and tan bodies? > There is only one progeny with maroon eyes and tan bodies (rrbb), so fraction = 1/8 |