Definition of "penetrance" []

• The frequency, under given environmental conditions, with which a specific phenotype is expressed by those individuals with a specific genotype. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "And seagrasses are especially sensitive to sediment since they need light for photosynthesis suspended sediments make the water less clear, reducing light penetrance."
• "The genetic data also show that the penetrance of Native Americans is very low in today's Central and Southern populations."
• "This, the penetrance of the BRCA gene in these families was only presumed, not measured."