Dictionary

evolution, biologic See biologic evolution.

evolution, cultural See cultural evolution.

evolutionarily conserved gene A gene that has remained essentially unchanged throughout evolution. Conservation of a gene indicates that it is unique and essential: There is not an extra copy of that gene with which evolution can tinker, and changes in the gene are likely to be lethal.

evolutionarily conserved sequence A base sequence in a DNA molecule (or an amino acid sequence in a protein) that has remained essentially unchanged throughout evolution.

Ewing sarcoma See sarcoma, Ewing.

exacerbation A worsening. In medicine, exacerbation may refer to an increase in the severity of a disease or its signs and symptoms. For example, an exacerbation of asthma might occur as a serious effect of air pollution, leading to shortness of breath.

exaggerated startle disease See hyperexplexia.

exam, pelvic See pelvic exam.

exam, rectal See digital rectal exam.

exanthem A rash on the outside of the body. By contrast, a rash on the inside of the body (for example, inside the mouth) is called enanthem. A patient with measles can have both exanthem and enanthem. See also enanthem; measles; rash.

exanthem subitum A sudden rash. See also measles.

excess iron An overload of iron that can damage the heart, liver, gonads, and other organs. See also iron excess.