Analysis of a 1963-bp polymorphic region flanking the human insulin gene.

The nucleotide sequence of a long polymorphic region located 365 bp upstream from the human insulin gene is reported. The region is composed of 139 repeating sequences whose consensus structure is related to ACAGGGGTGTGGGG. Expansion in the number of repeating sequences appears to have taken place through duplication and triplication of 112-141-bp regions. However, ancestral polymorphic regions containing additions or deletions of 50 bp or more were not detected in two previous generations.