DETECTION BY DGGE OF A NEW POLYMORPHISM CLOSELY LINKED TO THE ADENOMATOUS POLYPOSIS-COLI REGION

The EF5.44 locus is in close proximity to the chromosome 5 region to w hich the genetic defect responsible for familial adenomatous polyposis has been mapped. We have devised two oligonucleotides that promote th e specific polymerase chain reaction (PCR) amplification of a 365-bp s equence in this region. Analysis by denaturing gradient gel electropho resis of the resulting fragment has unravelled individual differences that could be identified as a single base pair change in a Mn/I restri ction site. This PCR assayable polymorphism increases the informativen ess at this locus, and should be useful in the presymptomatic diagnosi s of familial adenomatous polyposis.