Clustering of the human CLCA gene family on the short arm of chromosome 1 (1p22-31)

The CLCA gene family is a novel family of calcium-activated chloride channe ls. Several family members have recently been cloned from different mammali an species with distinct, highly tissue-specific expression patterns. Here, we describe radiation hybrid mapping of the human CLCA2 and CLCA3 genes us ing the Genebridge 4 panel. Both genes were mapped to adjacent loci on the short arm of chromosome 1 (1p22-31), a region to which the human CLCA1 had been assigned earlier. The results show clustering of all human CLCA family members known so far despite their moderately low levels of sequence homol ogy and their heterogeneous expression patterns.