How to synthesize a new kind of yeast cell — or person

September 19, 2011 by Amara D. Angelica
Yeast Cells

Yeast cells of the species Saccharomyces cerevisiae (credit: Jef D. Boeke and Sarah Richardson, Johns Hopkins University)

Scientists, in theory, could one day create whole new lifeforms, going way beyond simple cloning, new research at Johns Hopkins University School of Medicine suggests.

The scientists have now replaced the DNA in a yeast chromosome with computer-designed, synthetically produced DNA (structurally distinct from its original DNA), producing a healthy yeast cell.

So perhaps one day, a mad scientist could even create an entirely new kind of human. Think The Island of Dr. Moreau vs. The Boys from Brazil.

The researchers have also reported a method for changing the structure of the synthetic DNA, a process called “scrambling,” which could be applied to other organisms in addition to yeast.

Hey, I’m all for ways to create better beer. Can they make it non-fattening?

How to create better beer:

1. Produce “semi-synthetic” DNA based on a computer-generated blueprint for the sequence of nucleotides (the building blocks of DNA).

2. Use this new semi-synthetic DNA to replace the DNA in a chromosome arm of a yeast cell without impacting its health.

3. Next, scramble the synthesized DNA by adding a chemical to the yeast culture that causes major changes to gene-sized blocks of nucleotides in the synthesized DNA. By scrambling, some genes are lost and the order of other genes is shuffled.

4. Repeat this entire process in various yeast cultures to produce a multitude of modified yeast arms — just as shuffling and randomly removing cards from multiple decks would produce a multitude of different decks.

5. Synthesize all 16 yeast chromosomes to order to give the organism desired traits. (So far, only about one percent of the DNA in a yeast cell has been synthesized and scrambled through this research.)

6. Test your new beer. Repeat the process until you find one you like … or you’re pie-eyed. Biology is fun.

But why yeast? Because it’s used in many industrial fermentation processes, including the production of vaccines and biofuels. So being able to more efficiently confer desired traits on this organism may lead to the production of new vaccines and more efficient biofuels. Also, yeast is a eukaryote — its cells contain complex internal structures, such as a nucleus enclosed by a membrane. Because of these similarities between yeast cells and human cells, insights into cellular processes in yeast may yield insights into basic processes in human cells.

According to the National Science Foundation, this achievement represents a significant advancement for the field of synthetic biology — an emerging field in biology addressing the design and construction of new biological functions and systems not found in nature. Although researchers at the J. Craig Venter Institute have previously synthesized bacterial chromosomes, yeast chromosomes are larger and more complicated than them and so are more difficult to synthesize.

Ref.: Jessica S. Dymond, et al., Synthetic chromosome arms function in yeast and generate phenotypic diversity by design, Nature, 2011; [DOI:10.1038/nature10403]

Amara D. Angelica is Editor of KurzweilAI