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n a transformation experiment, DNA of a p+q+ strain was used to transform a reci

ID: 67037 • Letter: N

Question

n a transformation experiment, DNA of a p+q+ strain was used to transform a recipient strain that is auxotrophic for these markers. The number of each class of transformants is shown below:

a) If the total number of transformants isolated was 900, what is the co-transformation frequency for the p and q loci?
b) Diagram how each class of transformants were obtained starting with the recipient auxotroph. You should include one diagram of the recipient auxtroph, one diagram of the event that led to class 1, one diagram of the event that led to class 2, and one diagram of the event that led to class 3.

Class Genotype Number 1 p+q+ 405 2 p+q- 300 3 p-q+ 195

Explanation / Answer

a) cotransformation frequency = no of cell with p+q+/total

= 405/900 = 0.45 or 45%