Editing Biological determinism (section)

=== Germ plasm ===

{{main|Germ plasm}}

In 1892, the Austrian biologist [[August Weismann]] proposed that multicellular organisms consist of two separate types of cell: [[somatic cell]]s, which carry out the body's ordinary functions, and [[germ cell]]s, which transmit heritable information. He called the material that carried the information, now identified as [[DNA]], the [[germ plasm]], and individual components of it, now called [[gene]]s, determinants which controlled the organism.<ref>{{cite book |author=Weismann, August |author-link=August Weismann |year=1892 |title=Das Keimplasma: eine Theorie der Vererbung |trans-title=The Germ Plasm: A Theory of Inheritance |language=de |publisher=[[S. Fischer Verlag]] |location=Jena |url=http://www.esp.org/books/weismann/germ-plasm/facsimile/}}</ref> Weismann argued that there is a one-way transfer of information from the germ cells to somatic cells, so that nothing acquired by the body during an organism's life can affect the germ plasm and the next generation. This effectively denied that [[Lamarckism|Lamarckism (inheritance of acquired characteristics)]] was a possible mechanism of evolution.<ref>{{cite book |author=Huxley, Julian |author-link=Julian Huxley |year=1942 |title=Evolution, the modern synthesis |url=https://archive.org/details/in.ernet.dli.2015.280031 |publisher=Allen and Unwin |page=[https://archive.org/details/in.ernet.dli.2015.280031/page/n16 17]}}</ref> The modern equivalent of the theory, expressed at molecular rather than cellular level, is the [[central dogma of molecular biology]].<ref>{{cite book |last=Turner |first=J. Scott |editor1=Henning, Brian G. |editor2=Scarfe, Adam Christian |chapter=Biology's Second Law: Homeostasis, Purpose, and Desire |title=Beyond Mechanism: Putting Life Back Into Biology |chapter-url=https://books.google.com/books?id=naQm1_Lutq4C&pg=PA192 |year=2013 |publisher=[[Rowman & Littlefield]] |isbn=978-0-7391-7436-4 |page=192 |quote=Where Weismann would say that it is impossible for changes acquired during an organism's lifetime to feed back onto transmissible traits in the germ line, the CDMB now added that it was impossible for information encoded in proteins to feed back and affect genetic information in any form whatsoever, which was essentially a molecular recasting of the Weismann barrier.}}</ref>