epigenesis

[ ep-i-jen-uh-sis ]

noun

1. Biology. the theory that an embryo develops from the successive differentiation of an originally undifferentiated structure ( preformation ).
2. Genetics. the approximately stepwise process by which genetic information is modified and translated into the substance and behavior of an organism. epigenetics.
3. Geology. ore deposition subsequent to the original formation of the enclosing country rock.

epigenesis

/ ɪˈpɪdʒɪnɪst; ˌɛpɪˈdʒɛnɪsɪs /

noun

1. See preformation
   the widely accepted theory that an individual animal or plant develops by the gradual differentiation and elaboration of a fertilized egg cell Compare preformation
2. the formation or alteration of rocks after the surrounding rock has been formed
3. alteration of the mineral composition of a rock by external agents: a type of metamorphism

Derived Forms

• ˌepiˈgenesist, noun

Other Words From

• epi·gene·sist e·pig·e·nist [ih-, pij, -, uh, -nist], noun
• ep·i·ge·net·ic [ep-i-j, uh, -, net, -ik], adjective
• epi·ge·neti·cal·ly adverb

Word History and Origins

Origin of epigenesis¹

First recorded in 1800–10; epi- + -genesis

Example Sentences

Rignano calls his theory "centro-epigenesis" and is greatly influenced by Weismann.

From Project Gutenberg

The development is an epigenesis, or impressing on identical material of different characters by different surrounding forces.

From Project Gutenberg

It is interesting to display the essential contrast between preformation and epigenesis in the poetical words of Wolff himself.

From Project Gutenberg

Elsewhere he writes: 'I believe that I have established that ontogeny can be explained only by evolution, and not by epigenesis.'

From Project Gutenberg

In fact, the deepest consideration leads us again to the original question: Is embryonic development epigenesis or evolution?

From Project Gutenberg