Locus (plural, Loci)

A locus is the chromosomal "neighborhood" where a gene (a "house") resides; specifically, a potential disease-causing gene.

A locus is a location in one part of a chromosome where a particular gene(s) might reside, like a "house" (gene) might reside in a "neighborhood" (locus). Scientists who are looking for genes associated with retinal degenerative diseases call it a locus until they definitively prove that one (or more) gene(s) in this region cause(s) that disease.