C4 proteins (green) are seen at the synapses in a culture of human neurons. (Heather de Rivera/McCarroll Lab/Harvard via AP) Heather de Rivera/AP hide caption

A juvenile California two-spot octopus (Octopus bimaculoides). Michael LaBarbera/Nature hide caption

Sequencing the genes of a cancer cell turns up lots of genetic mutations — but some of them are harmless. The goal is to figure out which mutations are the troublemakers. Kevin Curtis/Science Source hide caption

Biologist Rob Knight, co-founder of the American Gut Project, recently moved the project to the University of California, San Diego's School of Medicine. Casey A. Cass/University of Colorado hide caption

Recent research sequenced 48 bird species, including (from left) the budgerigar, the barn owl and the American flamingo. (Left and center)iStock; (Right) Chris Minerva/Ocean/Corbis hide caption

This skull, from the Swedish archaeological site called Motala, is thought to have come from a hunter-gatherer who died there about 8,000 years ago. Anna Arnberg hide caption

Interpreting the results from a genome scan takes a lot of people time. And the databases used to interpret the results aren't infallible. iStockphoto hide caption

Rapid whole genome sequencing could provide timely treatment options for infants in intensive care. iStockphoto hide caption

The Proton Semiconductor Sequencer from Ion Torrent Systems Inc. is a new DNA sequencing machine designed to sequence the entire human genome in about eight hours for $1,000. Ethan Miller/Getty Images hide caption

Sara Terry and her son, Christian, in Spring, Texas. After sequencing Christian's genome, doctors were able to diagnose him with a Noonan-like syndrome. Eric Kayne for NPR hide caption

Watson, now 84, says sequencing helped explain his past sensitivity to certain drugs. But he didn't want to know everything his sequenced genome revealed about his health future. Courtesy of Cold Spring Harbor Laboratory hide caption