Sonnenburg, his wife Erica, and the graduate student Samuel Smits confirmed this idea in a recent experiment. The researchers started with mice that had been raised in sterile bubbles and then loaded with identical collections of gut microbes. They then fed these mice a high-fiber diet, before randomly switching half of them to low-fiber chow for seven weeks.
Predictably, the fall in fiber caused upheavals in the rodents' guts. In the low-fiber group, the numbers of 60 percent of the local microbe species fell dramatically, and some remained low even after the mice returned to high-fiber meals. Those seven low-fiber weeks left lingering scars on the animals' microbiomes.
Sulston worked alone, in silence, hunched over a microscope for eight hours a day. By studying and drawing worms of various ages, he figured out the ancestor and descendants of each of their cells. It was a monumental piece of science. Sulston mapped the complete history of an individual, the comprehensive family tree of a single body. "We had the entire story of the worm's cells from fertilized egg to adult," he later said, upon accepting the Nobel Prize for his work.
Known officially as the Tuskegee Study of Untreated Syphilis in the Negro Male, the 40-year experiment run by Public Health Service officials followed 600 rural black men in Alabama with syphilis over the course of their lives, refusing to tell patients their diagnosis, refusing to treat them for the debilitating disease, and actively denying some of them treatment.
For a study published Tuesday in the journal Nature Communications, Partridge and other researchers from Philadelphia suspended premature lambs, a close animal model for human fetuses, in a liquid-filled, artificial womb, allowing them to further develop for four weeks-longer than in past similar attempts.