Forked bristles, miniature wings, and sable bodies are all homozygous recessive traits whose genes are located on the same chromosome. You cross female flies that have forked bristles (f) with male flies that have both miniature wings (m) and sable bodies (s). You then cross the F1 of this cross with flies that have sable bodies, forked bristles, and miniature wings, and obtain the following numbers of offspring with the following phenotypes out of a total of 1500 offspring: Sable bodies and miniature wings 463 Sable bodies and forked bristles 3 Miniature wings and forked bristles 49 Forked bristles, miniature wings, sable bodies 99 Miniature wings 5 Wild type 107 Sable bodies 55 Forked bristles 514 A. Which are the parentals (non-recombinants)? B. Which are the double cross-overs?
Forked bristles, miniature wings, and sable bodies are all homozygous recessive traits whose genes are located on the same chromosome. You cross female flies that have forked bristles (f) with male flies that have both miniature wings (m) and sable bodies (s). You then cross the F1 of this cross with flies that have sable bodies, forked bristles, and miniature wings, and obtain the following numbers of offspring with the following
Sable bodies and miniature wings 463
Sable bodies and forked bristles 3
Miniature wings and forked bristles 49
Forked bristles, miniature wings, sable bodies 99
Miniature wings 5
Wild type 107
Sable bodies 55
Forked bristles 514
A. Which are the parentals (non-recombinants)?
B. Which are the double cross-overs?
C. Which gene is in the middle? Use your answers in parts A and B to explain your reasoning.
D. Calculate the distances between the gene in the middle with the genes on either end. Include in your answer the distances between each of the gene pairs, labeling the gene pair along with the distance. Show your work.
E. Is there any crossover interference? Explain your reasoning. Include the calculations of the coefficient of coincidence and interference in your answer.
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