DNA, the Language of Evolution:
Francis Crick & James Watson (2 of 2)

Life’s Cookbook
In the years that followed, Watson, Crick, and other researchers figured out the basics of how DNA works. Each gene, they realized, consists of a stretch of base pairs. A single-stranded copy of the gene was created (known as messenger RNA) and transported to protein-building factories in the cell called ribosomes. There, the sequence of the bases guided the assembly of a string of amino acids that became a new protein. When a cell divides, the double helix is unzipped and the DNA is replicated. It is life’s cookbook.

Using DNA
Evolutionary biology was revolutionized by the discovery of DNA. Mutations, researchers realized, change the spelling of the cookbook. A single base pair may change, or a set of genes may be duplicated. Those mutations that confer a selective advantage to an individual become more common over time, and ultimately these mutant genes may drive the older versions out of existence.