Scientists achieve the creation of a yeast cell with over half of its genome being artificial, marking a milestone in synthetic biology.
A group of scientists from the UK and the US successfully fused over seven synthetic chromosomes, crafted in the lab, into a single brewer's yeast cell (Saccharomyces cerevisiae). In essence, this marks the creation of the first eukaryotic cell with a membrane and nucleus, where over half of its genome has been artificially constructed. However, this cell was not entirely synthetic or artificial.
To achieve this feat, Saccharomyces cerevisiae was utilized, an organism utilized by humans for millennia. This makes it an ideal model as we possess an in-depth understanding of its genome. Sixteen chromosomes, the compacted form of DNA, were synthesized and then integrated into a live yeast nucleus.
The technique behind the research
Before insertion, unnecessary DNA segments underwent a purification process, while new DNA fragments were added to clearly label the artificial genes. Then, an algorithm was used to rearrange the gene arrangement within the chromosomes. All of this is akin to playing nature, but with a twist: convincing nature that our hands are trustworthy enough for seamless cell replication.
To stabilize the genome, numerous genes of a specific type of RNA were eliminated, while their presence was retained in a newly created artificial chromosome. This novel chromosome, named tRNA neochromosome, marks a milestone as it's entirely synthetic, a concept nonexistent in nature. This bold leap proved successful: not only did the cell survive, but it also initiated the replication process. A captivating achievement in the realm of cellular genetics.
A cell with half of its genome being artificial replicates normally
This marks a milestone as it is the first time a eukaryotic cell with more than 50% of its DNA originating synthetically has been developed, capable of surviving and replicating similarly to natural yeast strains. While bacterial and viral genomes have been synthesized previously, this represents the inaugural creation of a completely synthetic eukaryotic genome. The inclusion of the neochromosome in its genome renders this new yeast strain genetically distinct from its natural counterpart.
"We decided it was important to produce something that was heavily modified from nature's design. Our overall goal was to build yeast that can teach us new biology," adds consortium co-leader Jef Boeke, a biologist at NYU Langone Health.
Rewriting a yeast genome from scratch could result in a strain that's more resilient, faster, more tolerant to adverse conditions, and delivers superior performance.
Another step towards the still distant creation of synthetic life
Producing semi-synthetic yeast represents a significant step towards synthetic life but doesn't equate to creating artificial life. Over the years, several scientific teams have pursued this path. In 2010, John Craig Venter's Institute achieved a milestone by unveiling the first self-replicating cell with an entirely synthetic genome. However, that cell was vastly different from the current one, which is eukaryotic, akin to animal cells, for instance.
"Basic self-replicating cells were introduced as artificial in 2010."
Despite the quest to reconstruct life step by step, we have not yet succeeded in creating an artificial cell from scratch. Synthesizing a significant part of the genome and inserting it into existing cells is a remarkable achievement, but it does not constitute the generation of artificial life.
Written by Irene Rodríguez
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