FREQUENCIES OF THE BUTYRYLCHOLINESTERASE K-MUTATION IN BRAZILIAN POPULATIONS OF EUROPEAN AND AFRICAN ORIGIN

The frequency of the butyrylcholinesterase K mutation was calculated o n the basis of data obtained by polymerase chain reaction primer-intro duced restriction analysis (PCR-PIRA). The population sample was compo sed of 177 Brazilians: 95 whites of predominantly European ancestry an d 82 admired individuals (European and African origin). The frequencie s-18.4 +/- 2.8% for whites and 17.1 +/- 2.9% for admixed-did not diffe r from those previously obtained in North America, Scotland, Japan, an d Denmark, The occurrence of the K mutation in Europeans, East Asians, and Africans suggests a relatively old origin for this mutation, and the similar frequencies found in these populations may suggest the ope ration of selective forces.