Biochemistry, molecular genetics, and biology glossary terms for Companion Sites.


In pleiotropy a single gene is associated with more than one phenotype for an organism. A pleiotropic gene is also termed polyphenic gene.

Pleiotropic effects result from environmental, regulatory, and epigenetic phenomena that result in complex transcriptional responses involving multiple genes and regulons. (A regulon is defined as a group of transcriptional units or operons that are coordinately controlled by a regulator. Bacteria have operons, which are protein-encoding gene clusters.)

Examples of pleiotropic mechanisms:
● the cyclic-AMP concentration in a cell can produce a variety of effects because the cAMP second messenger controls protein kinases that affect a variety of proteins.
TNFR cluster of differentiation, CD30 binding by CD30L mediates pleiotropic effects, including cellular proliferation, activation, differentiation, and apoptosis..

. . . since 10/06/06