For more than 3 decades, researchers have been engineering microbes with the aim of harnessing these simple creatures to clean up pollution, make drugs, and produce biofuels. They have largely been limited to tinkering with individual genes, however. Now, two new developments, one of which is described in a paper published online this week by Science, have brought genetic engineers closer to a major goal: routinely manipulating sets of genes and even whole genomes.

Read the Science article.