preformation

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pre·for·ma·tion the·o·ry

archaic theory that the embryo was fully formed in miniature within a gamete at the time of conception.
See also: homunculus. Compare: epigenesis.

preformation

(prē′fôr-mā′shən)
n.
1. The act of shaping or forming in advance; prior formation.
2. A theory popular in the 1700s that all parts of an organism exist completely formed in the germ cell and develop only by increasing in size.

preformation

[-fôrmā′shən]
Etymology: L, prae + formatio, formation
an early theory in embryology in which the organism is contained in minute and complete form within the germ cell and after fertilization grows from microscopic to normal size. Compare epigenesis.

preformation

(prē-fawr-mā′shŭn)
In embryology, the development of structures from pre-existing templates, e.g., of bones from cartilage templates.
References in periodicals archive ?
Female inferiority continued to function as an axiom to justify preformationist theory.
David Depew argues that, according to recent scholarship, Darwin "held an epigenetic (rather than a preformationist or proto-Mendelian) conception of development.
30) In addition, he argues for the impossibility of such an occurrence on the basis of a preformationist theory of generation.