The field of synthetic biology has moved one step closer to a new frontier as a group of scientists has traversed one-third of the way to synthesising the complete genome of baker’s yeast, Saccharomyces cerevisiae.
An international team of researchers led by Jef Boeke, director of New York University Langone’s Institute for Systems Genetics, announced last Thursday that they constructed and integrated five “designer” chromosomes into Saccharomyces cerevisiae. This collaboration, known as the Synthetic Yeast 2.0 project (Sc2.0), unveiled the first-ever “designer chromosome” back in 2014, which brings the official total of made-from-scratch chromosomes to six of baker’s yeast 16.
In short, as reported by Discover Magazine, over 30% of a living organism’s genetic material can be substituted with artificial code, and it is only a matter of time before Sc2.0 researchers reach 100% – an entirely synthetic organism. Boeke told Discover that his team is aiming to finish all 16 chromosomes by the end of this calendar year.
Once, or when, they get there, apart from building the first synthetic, complex organism, a new generation of geneticists will be able to entertain many of the most vexing questions about the structure and function of genomes. Customised yeast cells will churn out novel medicines, biofuels and other useful compounds with more precision and speed than ever before.
Scientists have built designer cells in the past. In 2010, scientists at the J Craig Venter Institute created a bacterial cell controlled by a synthesised genome by copying the DNA of one bacterium into another. Last year they took the effort a step further by building the first “minimal cell,” an organism never found in nature that had the smallest number of genes required for life. Several months later, a team led by researchers at Harvard Medical School successfully re-engineered a small fraction of the genes of the bacterium E coli.
The new studies, however, signal an important advance. The chromosomes generated this time represent the largest amount of genetic material ever synthesised, and the new Sc2.0 cells are substantially different from their natural, or “wild type,” relatives. “In addition to building the thing, we have really added new features to chromosomes that were not there before,” said Boeke, as reported by Washington Post.
Unlike other synthetic organisms, the engineered yeast is a eukaryote – a complex cell with diverse internal structures, just like the cells in the human body. It has more genetic material than the bacteria synthesised by the Venter Institute and Harvard projects.
Yeast is among the most well-studied organisms on Earth, making it extremely useful for research. And it has myriad industrial, medical and scientific applications, from the production of biofuels to the development of vaccines. The Sc2.0 team plans to add a 17th chromosome to the designer cell to improve its protein-making machinery.
It took nearly 10 years for the researchers to build their first chromosome – even though they were working on the shortest one in the yeast’s genome. But they needed less than three years to generate the next five chromosomes, which include some of the genome’s longest. The process has gotten faster and given the confidence exuded by Boeke, his team might complete the project by the end of 2017 – an exciting development indeed.
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