Scientists uncover key mechanism in evolution: Whole-genome duplication drives

Summary

Sometimes, the most significant scientific discoveries happen by accident. Scientists have long known that whole-genome duplication (WGD) -- the process by which organisms copy all their genetic material -- plays an important role in evolution. But understanding just how WGD arises, persists, and drives adaptation has remained poorly understood. In an unexpected turn, scientists at Georgia Tech not only uncovered how WGD occurs, but also how it stays stable over thousands of generations of evolution in the lab. The new study was led by William Ratcliff, professor in the School of Biological Sciences, and Kai Tong, a former Ph.D. student in Ratcliff's lab who is now a postdoctoral fellow at Boston University. Their paper, "Genome duplication in a long-term multicellularity evolution experiment,"was published in Nature as the journal's cover story in March. "We set out to explore how organisms make the transition to multicellularity, but discovering the role of WGD in this process was completely serendipitous," said Ratcliff. "This research provides new insights into how WGD can emerge, persist over long periods, and fuel evolutionary innovation. That's truly exciting." A secret hidden in the data In 2018, Ratcliff's lab launched an experiment to explore open-ended multicellular evolution. The Multicellular Long-Term Evolution Experiment (MuLTEE) uses "snowflake" yeast (Saccharomyces cerevisiae) as a medium, evolving it from a single cell to increasingly complex multicellular organisms. The researchers do this by selecting yeast cells for larger size on a daily basis. "These long-term evolution studies help us answer big questions about how organisms adapt and evolve," said Tong. "They often reveal the unexpected and expand our understanding of evolutionary processes." That's exactly what happened when Ozan Bozdag, a research faculty member in Ratcliff's lab, noticed something unusual in the snowflake yeast. Bozdag observed the yeast when it was 1,000 days old and saw...