In 1948, Roger and Colette Vendrely reported a "remarkable constancy in the nuclear DNA content of all the cells in all the individuals within a given animal species", which they took as evidence that DNA, rather than protein, was the substance of which genes are composed.
En 1948, Roger e Colette Vendrely informaron da existencia dunha "salientable constancia no contido de ADN nuclear de todas as células de todos os individuos dunha especie animal dada", o que eles consideraron era unha evidencia de que o ADN, e non as proteínas, eran a substancia da que estaban formados os xenes.