Cite
 

Meaning of penetrance

pen•e•trance

Pronunciation: (pen'i-truns), [key]
— n. Genetics.
  1. the frequency, expressed as a percentage, with which a particular gene produces its effect in a group of organisms. Cf.(def. 2).
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.