A fly geneticist made a cross between females homozygous for three X linked rece
ID: 149433 • Letter: A
Question
A fly geneticist made a cross between females homozygous for three X linked recessive mutations (y = yellow body, ec = echinus, w = white eyes) and wild type males. He then mated the F1 females to triply mutant males and obtained the following results in the male progeny
UMales
UNumber
UAlleles in correct order
UNCO, DCO, SCOI or SCOII
+ + w
2
y ec +
3
y + +
10
+ + +
617
y ec w
610
+ ec w
9
y + w
23
+ ec +
30
Determine the order of the three loci y, ec, and w. SHOW ALL WORK. Draw the linkage arrangement and indicate where SCO I and SCO II would occur.
Reorder the alleles in the provided column if needed and determine whether each of the offspring classes is due to NCO, SCO I, SCO II, or DCO.
Calculate all map distances and draw a linkage map. SHOW ALL CALCULATIONS.
Calculate the interference and interpret the significance of the intereference number.
UMales
UNumber
UAlleles in correct order
UNCO, DCO, SCOI or SCOII
+ + w
2
y ec +
3
y + +
10
+ + +
617
y ec w
610
+ ec w
9
y + w
23
+ ec +
30
Explanation / Answer
THE DOUBLE CROSS OVERCLASS WHGICH ARE THE TWO WHICH ARE NOT OBERVED, ESTABLISH THE GENTIC ORDER :Y-W-EC.THUS THE F1 FEAMLE GENOTYPLE HAS THE ORDER Y W EC/+++THE DISTANCE BETWEEN W AND EC IS CALCULATED BY THE FREQUENCY RECOBINATION BETWEEN THE TWO GENES (8+7)/1000= 0.015
U MALES U NUMBERS U ALLELES IN CORRECT ORDER UNDO,DCO,SCOI,SCOII ++W 2 475 YEC+ 3 469 Y++ 10 8 +++ 617 7 Y EC W 610 18 + EC W 9 23 Y + W 23 0 + EC + 30 0Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.