Polymorphic human somatostatin gene is located on chromosome 3.

Somatostatin is a 14-amino-acid neuropeptide and hormone that inhibits the secretion of several peptide hormones. The human gene for somatostatin SST has been cloned, and the sequence has been determined. This clone was used as a probe in chromosome mapping studies to detect the human somatostatin sequence in human-rodent hybrids. Southern blot analysis of 41 hybrids, including some containing translocations of human chromosomes, placed SST in the q21 leads to qter region of chromosome 3. Human DNAs from unrelated individuals were screened for restriction fragment polymorphisms detectable by the somatostatin gene probe. Two polymorphisms were found: (i) an EcoRI variant located at the 3' end of the gene, found in Caucasian, U.S. Black, and Asian populations with a frequency of approximately 0.10 and (ii) a BamHI variant in the intron, which occurs in Caucasians at a frequency of 0.13.