Recombination
Recombination separates genes which are linked because they lie on the same chromosome.
In the heterozygote AaBbCc, the gametes which form can be either "parental" (ABC or abc) or "recombinant" (abC or Abc).
The frequency of the recombinant type depends on how close B is to C. This depends mainly on how physically close together B and C are on the same chromosome