11. The drosophila alleles for purple eyes (instead of red) and dumpy wings (ins
ID: 70857 • Letter: 1
Question
11. The drosophila 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, normal winged fly to a true breeding red eyed, dumpy winged fly.
You cross these F1 offspring 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 friend tells you that he thinks they are linked and that they are close enough to each other to have a frequency of recombinants of 0.38. If you are correct and they are on different chromosomes, how many purple eyed, normal winged flies would you ideally expect out of your 200 offspring? Your answer should be a whole number.
12.
The drosophila 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, normal winged fly to a true breeding red eyed, dumpy winged fly.
If your friend is correct and the genes are linked with frequency of recombinants of 0.38 how many purple eyed, normal winged flies would you expect? Your answer should be a whole number
Explanation / Answer
Original cross is eeDD (purple eyed, normal winged) crossed with EEdd (red eyed, dumpy winged).
All F1 will be EeDd.
Ans12... if genes are linked
F2 cross is EeDd X eedd. Parental types will be EeDd and eedd and recombinants will be eeDd (purple eyed, normal winged) and Eedd.
Recombination frequency is 0.38. So, no. of recombinants = 38 out of 100. 19 will be purple eyed normal winged if genes are linked and the rest 19 will be red eyed dumpy wings. The rest 62 will be parental types. Out of these 31 will be red eyed normal wings and the rest 31 will be purple eyed dumpy wings.
Ans 11. if genes are not linked, and are on different chromosomes,
then 1:1:1:1 ratio will be found. So, out of 200, 50 offsprings should be purple eyed, normal winged ideally.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.