Overview

Genetic markers are sequences of DNA located near defective or disease-causing genes that can be used to indicate the presence or absence of these genes. Genetic markers are always at the same place on a chromosome.

Several scientists hit upon the idea of markers at the same time. The association of a gene with a particular chromosome forms the basis of the field of cytogenetics. Cytogentics is a subdiscipline within genetics that links chromosomal variations to specific traits. Beginning with single-gene diseases, such as Duchenne muscular dystrophy, Huntington's disease, and cystic fibrosis, the search for genetic markers has mushroomed to an all-out hunt.

Along with these discoveries have come social and ethical debates over the use of genetic markers. To these debates has been added the idea of changing the problematic gene using gene therapy...