Using the technique of interrupted mating five Hfr strains w

Using the technique of interrupted mating, five Hfr strains were tested for the sequence in which they transmitted a number of different genes to an F- strain. Each Hfr starin was found to transmit it genes in a unique sequence as follows (only first six genes were scroed)

1.) FOPRSQ

2.) RPOFGY

3.) YXWQSR

4.) WQSRPO

5.) FGYXWQ

a. Show location and orientation of the F factor in each Hfr strain

b.) for each of the Hfr strains, state whic donor-gene markers should be seleted in the recipeients after conjugation to obtain the highest proportion of recombinants that will be Hfr?

Solution

Answer:

a. The four sequences should be arranged such that their regions of overlap are aligned.

FOPRSQ

YGFOPR

RSQWXY

OPRSQW

QWXYGF

So, location and orientation (from left to right in clockwise direction) of the F factor:

QSRPOFGYXW

b. The donor gene markers that should be selected to obtain the highest proportion of recombinants are:

Q, R, Y, W, F