In  the Drosophila white locus, the w^+/w genotype normally results in
   a wild-type red eyes.

   However,   if   the   wild-type   w^+  allele  is  translocated  to  a
   heterochromatic region (where gene expression is often inhibited), the
   eyes  are  mottled with red and white patches (variegated), reflecting
   intermittent  expression  of the dominant w^+ allele due to a position
   effect.