penetrancen.

1600 J. Norden Vicissitudo Rerum sig. C2 What in it hath chiefe Predominance, Hot, cold, drie, or moyst, meerely contraries, All in one body haue like penetrance.

1642 H. More Ψυχωδια Platonica sig. B7^v Sith that this withouten penetrance Of bodies may be done.

1911 Jrnl. Industr. & Engin. Chem. 3 17/2 (caption) Wood penetrance apparatus.

1926 A. W. Schorger Chem. Cellulose & Wood ix. 330 The pentosans appear to form a coating which resists penetrance by the mixed acid.

1966 A. Haddow in A. V. S. De Reuck & J. Knight Confl. in Society xv. 443 The horizontal axis indicates the increasing extent of penetrance, contact or understanding.

2000 Geriatrics (Nexis) 1 July 34 (note) Azithromycin has poor CNS penetrance and a high relapse rate.

1934 N. W. Timoféeff-Ressovsky in Biol. Rev. & Biol. Proc. Cambr. Philos. Soc. 9 433 The phenotypic manifestation of the mutant allelomorphs may be full and constant, or it can be variable and even dependent upon other factors (low penetrance, variable expressivity and specificity of the genes).

1946 R. R. Gates Human Genetics I. ii. 15 Lack of penetrance..has become a very important principle in human genetics... The gene is present in the germplasm, as shown by its transmission to the next generation, but for some reason it has completely failed to express itself in the soma.

1965 Punch 10 Nov. 689/2 The second complication is known as penetrance. When a gene affects every individual who carries it equally it is said to have 100 per cent penetrance.

1968 Brit. Jrnl. Psychiatry 114 1179/2 Manic-depressive disease may be a single dominant gene-transmitted disease with varying degrees of penetrance.

1990 Lancet 8 Sept. 599/1 Whether as a result of incomplete penetrance, gonadal mosaicism, or other mechanisms, for apparently unaffected parents of a child with tuberous sclerosis the risk of recurrence of the disease in each subsequent child is 2–5%.