This condition (medically called situs inversus totalis) involves complete transposition (right to left reversal) of the thoracic and abdominal organs. The heart is not in its usual position in the left chest, but is on the right. Specifically related to the heart, this is referred to as dextrocardia (literally, right-hearted).The stomach, which is normally in the left upper abdomen, is on the right. In patients with situs inversus totalis, all of the chest and abdominal organs are reversed and appear in mirror image when examined or visualized by tests such as X-ray filming. Situs inversus totalis has been estimated to occur once in about 6-8,000 births. Situs inversus occurs in a rare abnormal condition that is present at birth (congenital) called Kartagener’s syndrome.
- Reverse genetics
In molecular genetics, identifying genes purely on the basis of their position in the genome, with no knowledge whatsoever of the gene product. In classic genetics, the traditional approach was to find a gene product and then try to identify the gene itself. Also known as positional cloning.
- Reverse transcriptase
An enzyme that permits DNA to be made, using RNA as the template. A retrovirus, such as the HIV virus, can propagate itself by converting its RNA into DNA with reverse transcriptase.
- Reye syndrome
A sudden, sometimes fatal, disease of the brain (encephalopathy) with degeneration of the liver, occurs in children (most cases 4-12 years of age), comes after the chickenpox (varicella) or an influenza-type illness, is also associated with taking medications containing aspirin. The child with Reye (pronounced rye) syndrome first tends to be unusually quiet, lethargic (stuporous), […]
Radio frequency identification, a system for remotely storing and retrieving data. RFID tags can serve to identify and track medications.
Restriction fragment length polymorphism. A difference in DNA between people that can be recognized by the use of a restriction enzyme.