In a first, scientists have created a synthetic chromosome, advancing synthetic biology even further into the future. Scientists assembled the artificially-manufactured chromosome of a eukaryote, which was incorporated into a yeast cell. Thus, a life form that prospers and passes the genes down to its offspring has successfully supported the notion of “designer” genes.
The advance in synthetic biology is the first of an operational artificial chromosome in an organism more complex than a bacterium. The successful implantation of a chromosome in a multi-celled organism, like yeast, is truly remarkable due to its complex nature. This experiment opens the door to the creation of more artificial microbes that could be designed to manufacture better food products, more efficient fuels, and more potent medicines.
“We can shuffle genes into these chromosomes like a deck of cards,” said Jef Boeke, a geneticist at NYU. By mapping the genetic code of an organism, scientists are able to determine if certain chromosomes and the genes within them have the potential to metastasize and harm the organism. Furthermore, Boeke and his team have created a way in which the aforementioned genes can be removed and man-made genes can replace them to better serve the organism.
This isn’t the first time yeast has been used in genetic experiments. In 2009, scientists led by J. Craig Venter created the first synthetic bacterial genome inside of a yeast cell. Synthetic DNA, harbored within yeast cells, has been built to assemble artificial yeast chromosomes which have been used as a template for mapping genes for decades. Yeast was one of the original organisms to have its complete genome sequenced back in 1996.
The artificial chromosome embedded into the yeast, identified as “synIII,” builds upon a near decade-long legacy. For over seven years, the “Build a Genome” project has involved more than 60 biologists attempting to assemble a man-made chromosome for an organic system. The study’s researchers created the chromosome by using an organic template from the yeast cell. They used a stripped-down version of a third chromosome of the yeast that still contained 2.5 percent of the yeast’s original genes.
Geneticists have determined that within a yeast cell, only 1,000 of its 6,000 genes are vital to its stability and survival. Although 5,000 genes can be removed, some genes that are removed can create a cellular volatility when missing from the genetic code. To avoid harming the genes and the cell, researchers mapped every inessential gene on the artificial chromosome with sites that permitted them to be removed.
While creating an artificial version of an organism’s gene code may seem like typing letters to create sentences that make up the chapters of a book, the scientists did not follow this notion of a repetitive genetic code. Instead, they inserted a minute amount of synthetic genes into a natural yeast cell which were copied following the cell’s production of offspring. Along with the yeast’s natural chromosomes, through over 125 generations of offspring, the microbe’s artificial genes were stabilized.
Todd Kuiken of the Woodrow Wilson International Center for Scholars, located in Washington, D.C., stated that this is, “a major step towards being able to design completely novel organisms.” The significance of the project lies not in the creation, but the way in which the chromosome was produced. This example of synthetic genomics was intended to go far beyond just making copies of chromosomes, but changing the way in which a cell functioned to create a genetic code in its offspring.
The genome project is the next step in a brave new line of biology. Synthetic biology has the ability to produce new types of microbes with novel genetic codes that could create cheaper ways to process crude oil into automotive fuel or create new and improved medicines that do not contain harmful side effects. Although the science community is still awaiting the assembly of a whole artificial genome to create man-made versions of more complex multicellular organisms, such as plants and animals, the next chapter in biotechnology is promising.
By: Alex Lemieux