The length of a segment of DNA associated with the human insulin gene, which has been localized to the short arm of chromosome 11, is heterozygous in 63% of 52 individuals analyzed. This polymorphic region is approximately 500 base pairs from the nucleotide encoding the 5' end of insulin mRNA. The polymorphism appears to be due to an insertion or deletion of DNA sequences so that DNA fragments of different length are generated when DNA from a heterozygous individual is digested with selected restriction endonucleases.
