Question

Choose the correct answers from the alternatives given.
Determine the order of genes along a chromosome based on the following recombination
frequencies: AB, 8 map units; AC, 28 map units; AD, 25 map units; BC, 20 map units; BD, 33 map units

• A. A-C-D-B
• B. C-D-B-A
• C. D-A-B-C
• D. B-A-C-D

Answer 1

The correct option is C D-A-B-C

If the sequence is D-A-B-C as shown below then, AB will have a distance of 8 map units, AC will have a distance of 8+20 (AB+BC), AD will have a distance of 25 map units, BC will have a distance of 20 map units and BD will have a distance of 25+8 (AD+AB)= 33 map units. This fulfills the given requirements,

20+8=28 units

D-----------------------A----------------B----------------C

25 units 8 units 20 units

25+8=33 units

So, the correct option is 'D-A-B-C'.