How Many Genes Do Cells Need? Maybe Almost All of Them

By knocking out genes three at a time, scientists have painstakingly deduced the web of genetic interactions that keeps a cell alive. Researchers long ago identified essential genes that yeast cells can’t live without, but new work, which appears today in Science, shows that looking only at those gives a skewed picture of what makes cells tick: Many genes that are inessential on their own become crucial as others disappear. The result implies that the true minimum number of genes that yeast — and perhaps, by extension, other complex organisms — need to survive and thrive may be surprisingly large.