A
phenomenon of pedigrees in which a
gene is transmitted from one
affected face to other
through a phenotypically unaffected face, as by recessivity (especially for X-linked traits), epistasis,
variable expressivity, or
absence of an environmental challenge such as a toxin. Except at a crass
phenotypic level (e.g.,
clinical or commercial)
this term becomes progressively smaller useful as the mechanisms are elucidated.