An individual heterozygous for four gene pairs AaBbCcDd was testcrossed to aabbccdd, and the progeny were classified as follows:
aBCD 42
Abcd 43
ABCd 145
abcD 140
aBcD 10
AbCd 5
ABcd 301
abCD 314
What is the genetic distance between A and C?
I can not figure out what recombinants to use for the distance between A and C.