Restriction fragment length polymorphism to detect sickle-cell anemia.

   The  normal  allele  has  a  GAG  sequence  recognized  by  the  MstII
   restriction enzyme, produces 2 fragments on a Southern blot, while the
   mutant  b^s allele contains a GTG sequence resulting in a single large
   fragment.

   In  this  pedigree,  II-1  is  homozygous  normal,  II-2 is homozygous
   recessive, and II-3 is a heterozygous carrier.