Question

The relative location of four genes on a chromosome can be mapped from the following data on crossover frequencies Genes B and D Frequency of Crossover 5% Cand A 15% A and B 30% C and B 45% Cand D 50% Which of the following represents the relative positions of these four genes on the chromosome? 1. ABCD 2. ADCB 3. CABD 4. CBAD

Answer 1

Answer:

3. CABD

Explanation:

The gene mapping refers to providing position to the genes on the chromosomes.  The first gene map was constructed by the Alfred Sturtevant on the basis of recombinant produces or recombination frequency which was calculated.

The gene mapping refers to providing position to the genes on the chromosomes.

In the given question to construct gene map:

1. Look for the highest recombination frequency that is 50% between the C and D.

2. Now look for second-highest value and place the gene accordingly.

3.Similarly, place the genes in the decreasing order of recombination frequency and this will result that the sequence of the genes is- CABD.

Thus, Option-3 is correct.