The algorithm, developed by Michael Brent, the Henry Edwin Sever Professor of Engineering in the School of Engineering & Applied Science, is called NetSurgeon. It selects genes that need to be removed or silenced in the genome of a cell in order to coax it to perform a desired function, typically a normal thing the cell does but under atypical circumstances. Baker’s yeast cells, for example, will usually make a large amount of alcohol when fed a certain type of sugar –from edible corn kernels. When the NetSurgeon algorithm was applied in this case, the genetic alteration it recommended made the cells produce more alcohol when given a different kind of sugar from the inedible parts of corn plants. The research was published in the Proceedings of the National Academy of Sciences.
“Yeast have been engineered to make alcohol out of xylose, a type of sugar found in the woody parts of plants, but they don’t do it very well,” explained Brent. “We think the problem is not that they can’t do it, but that they don’t want to. So we have to convince them by making them use the same set of genes they use when they’re fed sugar from corn kernels. We sometimes think about this as causing the yeast to ‘hallucinate’ that they are in a sugar they like to turn into alcohol.”