The recombination frequency between the genes a & c is 5%, b & c is 15%, b & d is 9%, a & b is 20%, c & d is 24% and a & d is 29%. What will be the sequence of these genes on a linear chromosome?
- a, d, b, c
- d, b, a, c
- a, b, c, d
- a, c, b, d
Answer
(4) a, c, b, d
Solution
Recombination frequency is proportional to the distance between genes (1% = 1 map unit).
a – c = 5 and c – b = 15; a – b = 20 = 5 + 15
c lies between a and b.
b – d = 9; c – d = 24 = 15 + 9
b lies between c and d.
Check: a – d = 5 + 15 + 9 = 29, which agrees with the given value.
Gene sequence: a, c, b, d
Answer: (4)