Revolutionary new methods for extracting, purifying, and sequencing ever-more-ancient DNA have opened an unprecedented window into the history of life on Earth.
Two researchers sit hunched in front of a fume hood dressed head-to-toe in stark white Tyvek suits, though the yellow-tinted window I’m viewing them through lends the entire scene a sulfurous hue. One of the scientists, a research associate named Hongjie Li, pipettes tiny volumes of solutions containing decades-old DNA into centrifuge tubes, while the other, PhD student Lu Yao, types information into a laptop. Airlock doors and a sensitive ventilation system minimize the incursion of outside air and the myriad bits of contaminating DNA it carries. Yao, reaching a point when she can take a break, looks up from her work and waves, a smile spreading beneath her face mask and crinkling the corners of her eyes.
This is the ancient-DNA lab at the University of Illinois, Urbana-Champaign, tucked in a corner of the basement at the Carl R. Woese Institute for Genomic Biology. Yao has spent hours in this space. Working under the guidance of molecular anthropologist Ripan Malhi, she hopes to answer questions about phylogeny, biogeography, and island dwarfism among long-tailed macaques (Macaca fascicularis) in Southeast Asia by sequencing decades- and even century-old mitochondrial DNA collected from the dried skulls of monkeys in museum collections. And thanks to recent methodological, computational, and conceptual advances in the study of ancient DNA, Yao, Li—who studies ancient DNA from native Californians—and other researchers are succeeding, compiling sequences at an unprecedented rate.