Question

complete. Read carefully. Make a full complete presentation of your results. Place your answer, clearly organized, on the next page A. The fly characteristics brown eye and vestigial wing are both located on the fly chromosome II and they are approximately 20 mu apart. Please draw a complete presentation of a dihybrid test cross and the expected outcome from the cross. Show your cross, if you are using coupling or repulsion, the Punnett square associated and the predicted frequencies and numbers of offspring from and Fl of 1,000 offspring. 1. Clear representation of the chromosome involved and the gene loci relationship 2. 1llustration of the individuals involved in the cross, their genotypes and a list of the gametes each of them could produce. 3 Show your Punnett square for this cross with expected frequency and elassification (parental/recombinant) of the offspring produced. 4. Numbers of offspring out off 1,000 of each phenotype. Explanation why you can predict the numbers of each phenotype in the offspring generation B. You perform a cross with a wild type male fly and a female fly with a yellow body. The reciprocal cross has a female wild type crossed with a yellow body male. The resulting phenotypic ratio (cross 1) are 502 wild type females and 498 yellow body males. The reciprocal cross (cross 2) produces all Fl flies that are wild type. You conclude that: . The most likely mode of inheritance for yellow body characteristic is, and you decided this because? 2. You perform a similar experiment with the white eye characteristic and determine the same mode of inheritance is involved. Further you explore the loci positions of these genes and discover that they are approximately 8 mu apart on the same chromosome. If you had a female that was a heterozygous carrier for both characteristics, and her chromosomes were in coupling then the number of offspring from a cross with a white eyed-yellow bodied male. Show in an illustration this cross and associated information 3. IF 100 male offspring are produced: The number of Males that should be fully wild type. (red eyes, grey body) The number Males that should be red eyed and yellow bodied. 4. What prediction would you make about the female offspring that result from this cross? The female phenotypic ratio?

Answer 1

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