8. A true breeding red-eyed strain of fly is crossed with a true breeding white-eyed strain. All F1 had red eyes. F2 consisted of 175 red-eyed: 62 cream-eyed: 81 white-eyed. Provide the genotypes for the parents, F1 and F2 of this cross, and propose a biochemical pathway to explain the steps in pigment production affected by each gene.
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This suggests that two genes are involved in eye color, and that the alleles interact in an epistatic manner. Show more…
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An insect from a strain breeding true for white eyes was crossed to an insect from a strain breeding true for red eyes. The F1s all had white eyes. The F1 generation was crossed to produce an F2 generation that consisted of 243 white-eyed; 58 red eyed; 21 cream-eyed. a) Which phenomenon does these results illustrate? b) Provide genotypes for the parents, F1 progeny and F2 progeny of this cross. c) Draw a possible biochemical pathway that best explains the steps in pigment production, and indicate the step affected by each gene.
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In Drosophila, red eye color is dominant over brown eye color and pigmented ocelli (simple eyes located on the back of the head as opposed to the more prominent compound eyes) are dominant over white ocelli. A brown-eyed fly with pigmented ocelli is mated with a fly having red eyes and white ocelli, and some of their offspring have brown eyes and white ocelli. What are the genotypes of the parents? In Drosophila, gray body color is dominant over ebony, and straight wings are dominant over curved. A gray-bodied female with curved wings is mated with a gray-bodied male with straight wings, yielding some ebony, curved-wing offspring. What other types of offspring could be produced and in what proportions?
Normal eye color in flies is red. Mutant flies have brown eye color. Similarly, normal wing length is long. Mutant flies have short wings. A female true breeding fly with brown eyes and short wings is crossed with a true breeding male with red eyes and long wings. In the F1 the female flies are red eyed and long winged. The male flies are red eyed and short winged. F1 males are crossed to F1 females Both sexes of F2 progeny flies have phenotypes as shown: 30 red eyes long wings 30 red eyes short wings 10 brown eyes long wings 10 brown eyes short wings Describe the Genotype of the male and female parents. Deduce the inheritance of each Phenotype.
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