it is a heritable change in gene function without a change in the sequence of the DNA.
X inactivation is not restricted to females. It also occurs in males with Klinefelter syndrome who have more than one X chromosome.
The phenomenon of X inactivation is also called lyonization after the English geneticist Mary Lyon (1925-) who first described it.
- X, factor
A coagulation factor, a substance in blood essential to the normal clotting process. Production of factor X takes place in the liver and requires vitamin K. The gene for factor X is located on chromosome 13 and is in band 13q34. The “X” in factor X is the Roman numeral “ten.” (All numbered coagulation factors […]
A gene on the X chromosome that is located on the X chromosome. An X-linked disorder is associated with or caused by a gene on the X chromosome.
High-energy radiation with waves shorter than those of visible light. X-ray is used in low doses to make images that help to diagnose diseases and in high doses to treat cancer.
- X-ray crystallography
The use of X-rays of known wavelength to learn the structure of any crystalline material. Put otherwise, X-ray crystallography is a technology by which the locations of atoms in any crystal can be precisely mapped by looking at the image of the crystal under an X-ray beam. The crystal is placed in the beam of […]
- X-ray, AP
An X-ray picture in which the beams pass through the patient anteroposteriorly (from front to back).