Genetic mapping offers firm evidence that a disease transmitted from parent to child is linked to one or more genes. Mapping provides clues about which chromosome contains the gene and precisely where the gene lies on that chromosome. Genetic maps have been used successfully to find the gene responsible for relatively rare, single-gene inherited disorders such as cystic fibrosis and Duchenne muscular dystrophy. Genetic maps are also useful in guiding scientists to the many genes that are believed to play a role in the development of more common disorders such as asthma, heart disease, diabetes, cancer, and psychiatric conditions.
Credit: Darryl Leja, NHGRI.