Answer:
Explanation:
a). Order of genes = wx-v-sh
b).
Distance between gene wx and v = 7 m.u.
Distance between gene v and sh= 30 m.u.
Distance between gene wx and sh= 33.64 m.u.
c).
Coefficient of Coincidence=0.81
Interference=0.19
Exaplanatiion:
Hint: Always recombinant genotypes are smaller than the non-recombinant genotypes.
Hence, the parental (non-recombinant) genotype is Wx Sh V / wx sh v.
1).
If single crossover occurs between Wx & Sh..
Normal combination: Wx Sh / wx sh
After crossover: Wx sh / wx Sh
Wx sh progeny= 1515+280 = 1795
wx Sh progeny = 1531+292 = 1823
Total this progeny = 3618
The recombination frequency between Wx & Sh = (number of recombinants/Total progeny) 100
RF = (3618/10756)100 = 33.64%
2).
If single crossover occurs between Sh & V..
Normal combination: Sh V / sh v
After crossover: Sh v / sh V
Sh v progeny= 94+1531 = 1625
sh V progeny = 87+1515 = 1602
Total this progeny = 3227
The recombination frequency between Sh & V = (number of recombinants/Total progeny) 100
RF = (3227/10756)100 = 30%
3).
If single crossover occurs between Wx & V..
Normal combination: Wx V / wx v
After crossover: Wx v / wx V
Wx v progeny= 94+280= 374
wx V progeny = 87+292 = 379
Total this progeny = 753
The recombination frequency between Wx & V = (number of recombinants/Total progeny) 100
RF = (753 / 10756)100 = 7%
Recombination frequency (%) = Distance between the genes (mu)
Wx-------7mu------V-----------30mu--------------Sh
Locus1(Wx)------Locus 2(V)-------Locus 3 (Sh)
Expected double crossover frequency = (RF between Wx & V) * (RF between V & Sh)
= 7% * 30% = 0.021
The observed double crossover frequency = 87+94 / 10756= 0.017
Coefficient of Coincidence (COC) = Observed double crossover frequency / Expected double crossover frequency
= 0.017 / 0.021
= 0.81
Interference = 1-COC
= 1-0.81 = 0.19
