DNA. DNA is the molecule that is the hereditary material in all living cells. Genes are made of DNA, and so is the genome itself. A gene consists of enough DNA to code for one protein, and a genome is simply the sum total of an organism's DNA.DNA is long and skinny, capable of contorting like a circus performer when it winds into chromosomes.enes are made of DNA, and so is the genome itself. A gene consists of enough DNA to code for one protein, and a genome is simply the sum total of an organism's DNA. DNA is long and skinny, capable of contorting like a circus performer when it winds into chromosomes.