The yeast Saccharomyces cerevisiae isn’t exactly known for being tough, but when researchers propagated only the biggest yeast cells for thousands of generations, these single-celled fungi went from making snowflake-esque clusters “weaker than gelatin” to clumps “as strong as wood” and 20,000 times the size of initial flakes. Partly to thank for this impressive transformation is the chaperone protein Hsp90, which helps fold other proteins into their proper shapes, School of Biological Sciences Associate Professor William Ratcliff and his colleagues report.