An individual heterozygous for four genes, AaBbCcDd, is testcrossed and 1000 progeny are classified by the gametic contribution of the heterozygous parent as follows:

AbCd 9
abCD 310
aBcD 6
aBCD 42
abcD 145
ABcd 305
ABCd 140
Abcd 43

Which if any of these genes are linked?

What must have been the genotype of the original parents that produced the heterozygote above?

What would be the order of these genes?

What is the interference value? ”