Questions 9-15 are related. The dorsophila alleles for purple eyes (instead of r

Question

Questions 9-15 are related. The dorsophila alleles for purple eyes (instead of red) and dumpy wings (instead of normal) are both recessive. Gene "E" designates eye color (E: dominant, e: recessive), and gene "D" designates wing shape (D: dominant, d: recessive). You cross a pure breeding purple eyed, nomral winged fly to a true breeding red eyed, dumpy winged fly.

9.) What are the genotypes of the parental flies

10.) What would you expect the offspring(F1) phenotypes to be?

11.) You cross these F1 offsprings to flies that are pure breeding for purple eyes and dumpy wings. You get 200 offspring. 45 are purple eyed and dumpy winged, 43 are red eyed and normal winged, 63 are purple eyed and normal winged, and 49 are red eyed and dumpy winged. you think that these two genes could be on different chromosomes but your firnd tells you that he thinks they are linked and that htye are close enough to each other to have a frequency of recombinants of 0.38. If you are corrct and they are on different chromosomes, how much purple yeed, normal winged flies would you ideally expect out of your 200 offspring? (Your answer should be a whole number.)

12.) If your firnd is correct and the genes are lined with frequency of recombinatns of 0.38 how many purple eyed, normal wiged flies would you expect?

13,) Calcualte the chi squared value if the genes are on different chromosmes.

14.) Calcualte the chi squared value if your friend is correct.

15,) who is more likely to be correct? I am? or my Firend is?

Explanation / Answer

9.genotypes of parental flies:

purple eyed,normal wing-eeDD

red eyed,dumpy wing-EEdd

10. F1 phenotypes: eeDD*EEdd

11.F1 offspring crossed with purple eyes and dumpy wings

EeDd*eedd

if the genes are on different chromosome the expected purple eyed normal winged flies would be 1/4*200=50 as the ratio of the offsprings then would have been 1:1:1:1

12.if my friend is correct i.e the genes are linked then the expected value of purple eyed normal wing would be 9/16*200=113(rounded to whole number)

13.chi square if the genes are on different chromosome

null hypothesis:1:1:1:1

degree of freedom:4-1=3

conclusion:the calculated X2 value is 4.88 which is less than the tabulated value(7.82) at df 3 and 5% level of significance.so null hypothesis is accepted.

14.chi square if the genes are on same chromosome

null hypothesis:9:3:3:1

degree of freedom:4-1=3

conclusion:the calculated value of X2 is 101.22 which is more than the tabulated value(7.82) at df 3 and 5% level of significance.so null hypothesis is rejected

15.the genes are present on different chromosome as we can conclude by the X2 values. so the friend is wrong

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