Identify the basis for chromosome mapping in the HfrFcrosses

Identify the basis for chromosome mapping in the Hfr×Fcrosses.

a. The point of insertion and the direction of transfer are not fixed. Breaking the conjugation tube at different positions produces partial diploids with corresponding portions of the donor chromosome being transferred. The mapping of genes is based on point of insertion

b. The point of insertion is fixed, but the direction depends on the type of F. The length of the chromosome being transferred is constant, so mapping does not depend on time.

c. The point of insertion depends on the type of F. This affects the direction of transfer. Breaking the conjugation tube produces either diploid or haploids with the donor chromosome being fully transferred. The mapping of genes is based on the point of insertion and direction of the transfer.

d. The point of insertion and the direction of transfer are fixed. Breaking the conjugation tube at different times produces partial diploids with corresponding portions of the donor chromosome being transferred. The mapping of genes is based on time.

Solution

The answer is D.

d. The point of insertion and the direction of transfer are fixed. Breaking the conjugation tube at different times produces partial diploids with corresponding portions of the donor chromosome being transferred. The mapping of genes is based on time.