A detectable genetic trait or segment of DNA that can be identified and tracked. A marker gene can serve as a flag for another gene, sometimes called the target gene. A marker gene must be on the same chromosome as the target gene and near enough to it so that the two genes (the marker gene and the target gene) are genetically linked and are usually inherited together.
- Marker, blood
A sign of a disease or condition that can be isolated from a blood sample. For example, the monoclonal antibody D8/17 is a diagnostic sign of pediatric autoimmune disorders associated with streptococcus.
- Marker, tumor
A substance that can be detected in higher-than-normal amounts in the blood, urine, or body tissues of some patients with certain types of cancer. A tumor marker may be made by a tumor itself, or it may be made by the body as a response to the tumor. Tumor marker tests are not used alone […]
Resembling marble. For example, the bone in osteoporosis appears marmoreal. From the Latin noun “marmor” meaning “marble.”
- Marriage, cousin
A form of consanguinity. Everyone carries recessive alleles, genes that are generally innocuous in the heterozygous state but that in the company of another gene of the same type are capable of causing disease. We are all genetic reservoirs for genetic disease. Since first cousins share a set of grandparents, for any particular allele (gene) […]
- Marshall-Smith syndrome
A disorder characterized by advanced bone age at birth, broad forehead, prominent eyes, and small chin. There is difficulty feeding, failure to thrive, retarded psychomotor development, and predisposition to respiratory infection. It may be fatal within the first years of life. The cause of the syndrome is unknown. It is named for Richard E. Marshall […]