Top: Science: Biology: Genetics: Terminology: M




[ history ]

malformation

A structural defect inherited in an organ or part of an organ that results from abnormal fetal development.


[ history ]

mapping

The process of deducing schematic representations of DNA. Three types of DNA maps can be constructed: physical maps, genetic maps, and cytogenetic maps, with the key distinguishing feature among these three types being the landmarks on which they are based.


[ history ]

marker

Also known as a genetic marker, a segment of DNA with an identifiable physical location on a chromosome whose inheritance can be followed. A marker can be a gene, or it can be some section of DNA with no known function. Because DNA segments that lie near each other on a chromosome tend to be inherited together, markers are often used as indirect ways of tracking the inheritance pattern of genes that have not yet been identified, but whose approximate locations are known.


[ history ]

melanoma

Cancer of the cells in the skin that produce melanin, a brown pigment. Melanoma often begins in a mole.


[ history ]

Mendelian inheritance

Manner in which genes and traits are passed from parents to children. Examples of Mendelian inheritance include autosomal dominant, autosomal recessive, and sex-linked genes.


[ history ]

messenger RNA

(mRNA) Template for protein synthesis. Each set of three bases, called codons, specifies a certain protein in the sequence of amino acids that comprise the protein. The sequence of a strand of mRNA is based on the sequence of a complementary strand of DNA.


[ history ]

metaphase

The phase of mitosis, or cell division, when the chromosomes align along the center of the cell. Because metaphase chromosomes are highly condensed, scientists use these chromosomes for gene mapping and identifying chromosomal aberrations.


[ history ]

microarray technology

A new way of studying how large numbers of genes interact with each other and how a cell's regulatory networks control vast batteries of genes simultaneously. The method uses a robot to precisely apply tiny droplets containing functional DNA to glass slides. Researchers then attach fluorescent labels to DNA from the cell they are studying. The labeled probes are allowed to bind to complementary DNA strands on the slides. The slides are put into a scanning microscope that can measure the brightness of each fluorescent dot; brightness reveals how much of a specific DNA fragment is present, an indicator of how active it is.


[ history ]

microsatellite

Repetitive stretches of short sequences of DNA used as genetic markers to track inheritance in families.


[ history ]

mitochondrial DNA

The genetic material of the mitochondria, the organelles that generate energy for the cell.


[ history ]

monosomy

Possessing only one copy of a particular chromosome instead of the normal two copies.


[ history ]

mouse model

A laboratory mouse useful for medical research because it has specific characteristics that resemble a human disease or disorder. Strains of mice having natural mutations similar to human ones may serve as models of such conditions. Scientists can also create mouse models by transferring new genes into mice or by inactivating certain existing genes in them.


[ history ]

multiple endocrine neoplasia, type 1

(MEN1) A rare inherited disorder that affects the endocrine glands, which release hormones into the bloodstream. The disorder, also known as Wermer's syndrome, can cause multiple tumors in the parathyroid and pituitary glands and in the pancreas. These tumors are almost always benign, but they can cause the glands to become overactive and secrete abnormal levels of hormones. Those abnormal secretions, in turn, can cause a variety of medical problems, ranging from kidney stones and fatigue to fertility problems and life-threatening ulcers.


[ history ]

mutation

A permanent structural alteration in DNA. In most cases, DNA changes either have no effect or cause harm, but occasionally a mutation can improve an organism's chance of surviving and passing the beneficial change on to its descendants.



 All text is available under the terms of the GNU Free Documentation License. (See Copyright Policy for details.) 
© Open-Site Foundation, Inc.
Hosted by Android Technologies, Inc. the medical robotics news source.
Visit our sister sites dmoz.org | mozilla.org | chefmoz.org | musicmoz.org