Determine the sequence of genes along a chromosome based on the following recombination frequencies:A-B-8 map units A-C-28 map units A-D - 25 map units B-C 20 map units B-D-33 map units

C B A D.

Explanation:

The recombinants can be produced by the crossing during the meiosis. The sequence of the genes can be known by the distance of the recombination frequencies.

The gene sequence problem can be solved by selecting the largest map distance and then placing the genes involved at the opposite ends of the line. This represents the portion of the chromosome. B and D genes must be put farthest as much as possible. The A and B distance is 8 which we can get by subtracting the A-D and B-D distance.

Thus, the answer is C B A D.