Talking Glossary of Genetic Terms
A locus is the specific physical location of a gene or other DNA sequence on a chromosome, like a genetic street address. The plural of locus is "loci".
"Locus" is a term that we use to tell us where on a chromosome a specific gene is. So it's really the physical location of a gene or of a DNA polymorphism on a chromosome. And it's sort of like a street address for people. And one of the things that we think about when we're thinking about genes and chromosomes is we may think of the chromosome as a country, and then a region of a chromosome would maybe be the city, and then we'll get down to a very specific area, which is the locus, and that would be equivalent to, say, a person's street address. And that's the street address of that gene. An important thing to remember is that the plural of "locus" is "loci", not "locuses".
Name: Joan E. Bailey-Wilson, Ph.D.
Occupation: Co-chief and Senior Investigator, Inherited Disease Research Branch; Head, Statistical Genetics Section
Biography: Dr. Bailey-Wilson develops new statistical methods and software and performs analyses that guide other genome scientists hunting for disease-associated genes. Trained in statistical genetics, she is interested in understanding the genetics of complex diseases and developing novel methodologies that can be used to disentangle the roles that genes and environment play in causing disease. Collaborating with other researchers, Dr. Bailey-Wilson studies a range of diseases, including lung cancer, prostate cancer, breast cancer, myopia and other eye diseases, and cleft lip and palate.