11. 1 what is the evidence that the gene is dna? y a new dye was developed that could bind specifically to dna and turned red in direct proportion to the amount of dna present in a cell. This technique proved circumstantial evidence that dna was the genetic material: Dna was confirmed to be an important component of the nucleus and the chromosomes, which were known to carry genes. When cells from different species were stained with the dye and their colour intensity measured, each species appeared to have its own specific amount of nuclear dna. The amount of dna in somatic cells (body cells not specialized for reproduction) was twice that in reproductive cells (eggs or sperm) as might be expected for diploid and haploid cells, respectively. y. In the 1920s, griffith was studying the bacterium streptococcus pneumonia, or pneumococcus, one of the agents that cause pneumonia in humans. He was trying to find a vaccine against the illness.