In 2010, geneticist Craig Venter unveiled the world's first synthetic organism - a variant of a bacterium that causes infections in goats. In April, researchers took a step toward a much more useful synthetic microbe, synthesizing from scratch one of the 16 chromosomes of Saccharomyces cerevisiae, or baker's yeast. Yeasts, like humans, are eukaryotes: They have complex DNA packaged in chromosomes and riddled with introns (pieces of DNA that don't contribute to the final protein) and "junk DNA" with no known purpose. To simplify their task, researchers first searched the computerized genetic code of one chromosome - chromosome 3 - and deleted introns and junk DNA. They added in code to create 98 ready-made cutting sites, like perforations in a sheet of paper, throughout the chromosome. That way, future researchers can pop out various genes and study the effects. Eventually, getting rid of all the non-essential genes would result in a bare-bones yeast with the minimum number of genes possible.
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