Question

E. coli strain B is doubly infected with two rII mutants of phage T4. 0.2 ml of a 108 dilution of the progeny is plated on E. coli B and 0.1 ml of a 104 dilution of the progeny is plated on E. coli K. 16 plaques appeared on strain B, 400 on strain K. Calculate the recombination frequency between these two mutations.

Answer 1

To Find :

The recombination frequency between these two mutations.

Solution :

Formula of calculating recombination frequency is :

$R.F = \text{Number of mutations}\times \dfrac{\text{number of k plaques} \times D.F }{\text{Volume used}}\times \dfrac{Volume'}{\text{Number of B plaques} \times D.F' }}$

Putting all given values in above equation, we get :

$R.F = \dfrac{2\times 400\times 0.2 \times 10^4}{16\times 0.1\times 10^8}\\\\R.F = 0.01$

Therefore, the recombination frequency between these two mutations is 0.01 or 1 %.