This pedigree shows a family affected
   by a dominant trait.

   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.