To find the chromosome region containing the affective gene, markers from a number of chromosomes were sequentially tested for linkage with the disease gene. This led to the identification of the hereditary pancreatitis locus on chromosome 7.

On the right is a statistic plot that proved that this region of DNA likely carried the hereditary pancreatitis gene.

The hereditary pancreatitis gene was on the same chromosome as the cystic fibrosis gene, and at the exact location of the T-cell receptor beta chain gene. This finding was important because the DNA sequence for TCRB was known and it contained the trypsin genes.

Whitcomb et al. GASTROENTEROLOGY 110:1975, 1996