Scientists at New York University have successfully synthesized a chromosome of yeast. It may not sound much, but it’s arguable the most complex DNA synthesis to date and the closest step towards doing so with animals.
It’s now four years since the J Craig Venter Institute created a synthetic cell of bacteria, something it described at the time as “the first self-replicating species we’ve had on the planet whose parent is a computer.”
Now an NYU team has done the same thing with a chromosome of yeast. Although you might imagine that yeast is closer to bacteria than to a human, Popular Science explains that in terms of DNA that’s not the case. Yeast is a single-cell organism (pictured), but its DNA is structured in a more complex fashion than bacteria. Whereas bacteria falls into a category of simple organisms called prokaryotes, yeast is a eukaryote, the same category that covers plants and animals.
According to Jef Boeke, who led the NYU project, synthesizing the yeast chromosome wasn’t a major advance in principle from the work done on bacteria. After the bacteria synthesis, researchers knew in principle that doing the same with a yeast chromosome was possible and it was just a case of actually doing it.
The big change this time round is that the researchers actually manipulated the DNA in the chromosome, rather than merely copying it. The changes meant that although the synthesized chromosome works just like the original (something they tested by inserting it into natural yeast, which developed as normal), it’s set up to respond to the addition of an extra chemical. This triggers the synthesized chromosome to rearrange itself at random, something that’s been described as almost like an evolution simulator.
Yeast is made up of 16 chromosomes and the one that’s been synthesized is responsible for around three percent of its total DNA. Synthesizing all 16 chromosomes will be the next goal.
As far as practical benefits go, the random scrambling feature could eventually be used to try to create yeasts that help medicines for malaria or a vaccine for hepatitis B, as well as improving biofuels.
(Image credit: Frankie Robertson.)