Abstract
Restriction endonuclease mapping of the human globin genes revealed a genetic variation in a Hpa I recognition site about 5000 nucleotides from the 3'' end of the .beta.-globin structural gene. Instead of a normal 7.6-kilobase (kb) fragment which contains the .beta.-globin structural gene, 7.0-kb and 13.0-kb variants were detected. Both variants were found in people of African origin and were not detected in Asians or Caucasians. The 13.0-kb variant is frequently associated with the sickle Hb mutation and may be useful for the prediction of the sickle cell gene in prenatal diagnosis. Polymorphism in a restriction enzyme site considered as a new class of genetic marker and may offer a new approach to linkage analysis and anthropological studies.