Instead of just copying nature, the team did extensive tinkering with their chromosome, deleting unwanted genes here and there. It then successfully incorporated the designer chromosome into living yeast cells, endowing them with new capabilities not found in naturally occurring yeast.
The most familiar yeast is commonly referred to as brewers’ yeast, saccharomyces cerevisiae, which is a unicellular eukaryotic microorganism that belongs to the fungi kingdom. This microorganism has been extremely relevant to the human population for thousands of years due to the fact that it consumes sugars and produces alcohol under anaerobic conditions. Many scientists and anthropologists alike agree that it was the thirst for beer that led humans to farm barley back in 9000 BC. Beer as well arguably helped fight many diseases. Much of the water in Medieval Europe was undrinkable, but once put through the brewing process it became suitable for human consumption. There is remarkable evidence that sustains the fact that beer helped the Mesopotamian civilization form, but that is another story for another time.
Recently scientists, for both academia and industry, have been genetically modifying the metabolic pathways of the yeast to produce many more compounds besides ethanol. Products of yeast are now being used to manufacture medicines, other fuels besides ethanol, lubricants, polymers and plastic additives, fragrances, and cosmetics (Check out Amyris ). There are so many applications for this microorganism, but getting the wild yeast to behave the way you want, and produce what is desired is not so easy. It would be much easier if it was possible to print the entire genome, mutant free, and this is exactly what an international team of scientists is working on.
This international team of scientists, led by Jef Boeke, has successfully synthesized the first of 16 chromosomes that codes for the genetic makeup of this microorganism. Although a wild yeast strain is roughly 12 Mb in size there are many nonessential genes that do not make proteins, that scientists believe can be left out without compromising fitness. The gene which scientists chose to work on is saccharomyces cerevisiae’s chromosome III, which is the smallest chromosomes and delegates how yeast cells mate and undergo genetic change. The scientists inserted their synthetic chromosome, which has over 50,000 deleted base pairs from the original, into living yeast cells and it grew just as well as normal yeast. Other teams around the world are working on slimming down the other chromosomes, which will one day lead to an entirely synthetic yeast chromosome free of what scientists call "jumping genes," which are lengths of DNA that randomly jump around the genome and cause mutations. Boeke thinks that there will be synthetic versions of the entire organisms chromosomes by 2017.
Once we are able to completely build a yeast cell from scratch scientists will be able to code and print the organism to behave any way we want, and more efficiently produce the all the medicines, biofuels, and other products that we desire.
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Picture from Livescience .