Haplotypes, coupling (in cis), and repulsion (in trans)

Schematic representation of two pairs of chromosomes, to illustrate that the coupling (in cis) and repulsion (in trans) relationships of the alleles affect the haplotypes.

• In the top pair of chromosomes, the B1 and C1 alleles are in coupling (in cis).
• In the bottom pair of chromosomes, the B1 and C1 alleles are in repulsion (in trans).

The individual marker genotypes are the same in both cases, but the haplotypes differ. A, B, and C each represent loci; the subscripts represent alleles at these loci.