A’S, T’S, G’S, AND C’S ARE ALL IT TAKES TO MAKE YOU, ME, OR A banana. Unique strings of these molecules, matched up in units called base pairs, form doubled DNA helixes, which serve as the recipes for all living things. Because the challenges of life—such as absorbing nutrients, replicating, and moving—are fairly consistent across organisms, there’s plenty of overlap between sequences. Here’s a sampling.
ALL LIVING THINGS
To compare across distant species—whose codes diverge too greatly to lay side by side—scientists look for overlaps in the molecules DNA produces, such as proteins. Both fruit flies and humans, for instance, rely on the Wnt family of proteins to establish the back and belly of the embryo.
PRIMATES
Analyzing DNA line by line works fine within the same phylogenetic family, where…
