ELI5 DNA - what is the double helix?

If there's 3.2 billion base pairs in the human DNA, how come there's only about 20,000 genes? What is a gene? What is the double helix? Why is it significant? Who deserves credit for the discovery of DNA? Why do some people think Rosalind Franklin should have been awarded a Nobel Prize? ... we explain like I'm five Thank you to the r/explainlikeimfive community and in particular the following users whose questions and comments formed the basis of this discussion: 1994x, coolbeans1114, xandarg and nickcagefan2 To the ELI5 community that has supported us so far, thanks for all your feedback and comments. Join us on Twitter: https://www.twitter.com/eli5ThePodcast/ or send us an e-mail: [email protected]