Germ plasm
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2008-05-13T13:02:59Z
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Reverted edits by [[Special:Contributions/59.95.108.167|59.95.108.167]] ([[User talk:59.95.108.167|talk]]) to last version by Toddst1
{{Mergefrom|Germplasm|Talk:Germ plasm#Merger proposal|date=October 2007}}
'''Germ plasm''' or '''polar plasm''' is a zone found in the cytoplasm of the [[egg cell]]s of some [[model organisms]] (such as ''[[Caenorhabditis elegans]]'', ''[[Drosophila melanogaster]]'', ''[[Xenopus laevis]]''), which contains determinants that will give rise to the [[germ cell]] lineage. As the zygote undergoes [[mitosis|mitotic]] divisions the germ plasm is ultimately restricted to a few cells of the [[embryo]], these germ cells then migrate to the [[gonad]]s.
==Germ plasm theory==
The germ plasm theory is a hypothesis concerning the ability to become germ cells, which is now proven wrong. <ref> [http://www.esp.org/books/weismann/germ-plasm/facsimile/title3.html The Germ-Plasm: A Theory of Heredity by August Weismann]</ref>
The term germ plasm was first used by the German biologist [[August Weismann]] (b.1834-d.1914) to describe a component of [[germ cell]]s that he proposed were responsible for [[heredity]], roughly equatable to our modern understanding of [[DNA]]. August Weismann formulated the now defunct [[germ plasm theory]] in 1893, in which he stated that the germ plasm was the essential nuclear part of germ cells, that it remained qualitatively unchanged from the zygote (in contrast with somatic cells) and was responsible for heredity. In other words it states that a gene's determination was sealed as it, and each of its offspring received fewer and fewer genes from what he called the "germ plasm." (That there is only a set "amount" of "germ plasm" (what we know as genes) and that it was gradually divided amongst the offspring). Cases such as Dolly (the famous cloned ewe) which, via [[somatic cell nuclear transfer]], proved that adult cells retain a complete--as opposed to Weissman's increasingly determined gradual loss of genetic information--set of information; finally putting Weismann's theory to rest.
==Germ plasm==
*[[Germplasm]], the collection of genetic resources
==References==
<references/>
[[Category:Germ cells]]