Southern blots of an RFLP locus on chromosome 17 shows close linkage with the disease phenotype.

For example, individuals III-2 and III-3 are affected, and received an A allele from the mother and a B allele from the affected father.

This suggests that the disease locus is closely linked to the RFLP locus on chromosome 17.

Such linkage data can be used to map genes on chromosomes.