Germ plasm

The related idea that information cannot pass from somatic cells to the germ line, contrary to Lamarckism, is called the Weismann barrier.

Thus, the historian of science Rasmus G. Winther states, Weismann was not a Weismannian, as he, like Darwin, did believe in the inheritance of acquired characteristics, which later came to be known as Lamarckian.

[2] The part of Weismann's theory which proved most vulnerable was his notion that the germ plasm (effectively, genes) was successively reduced during division of somatic cells.

[5] Cases such as Dolly, the cloned sheep, proved via somatic cell nuclear transfer that adult cells retain a complete set of information – as opposed to Weismann's increasingly determined gradual loss of genetic information – putting this aspect of Weismann's theory to rest as a general rule of metazoan development.

[6] The idea was to some extent anticipated in an 1865 article by Francis Galton, published in Macmillan's Magazine, which set out a weak version of the concept.