Scientists create yeast using synthetic DNA
Allison Snyder reports via Axios: For more than 15 years, scientists have worked to build a complex cell containing an entire genome built from scratch. This week they announced a major breakthrough: they created artificial copies of 16 chromosomes in a yeast cell and succeeded in fusing some of them into a single cell. The breakthrough reveals new information about basic processes in cells, and is a key step toward some scientists’ vision of creating programmable cellular factories to produce biofuels, materials, medicines and other products.
The changes researchers have made to yeast chromosomes fall into three main categories: increasing genome stability, reusing codons (genetic sequences that carry instructions for reading DNA or RNA) and introducing a system that allows scientists to create millions of cells, each with different genes. Properties. “A big problem is that a lot of the things you want to make are actually toxic to cells,” says Benjamin Blount, a synthetic biologist at the University of Nottingham in the UK and co-author of some of the papers in a series published this week in Cell and Cell Genomics. Work details). With a system that effectively re-edits the genome and mimics evolution, scientists can make many types of yeast and choose the ones that are “really good at growing under what you’re trying to make.” They are then able to look at what happened to their genomes to enable that particular strain to grow and make the desired product, and use that genetic information to develop strains of yeast suitable for an industrial process.
The chromosomes still have to be integrated into a single cell that can survive, which means they must be “essentially indistinguishable” from normal chromosomes in terms of cell viability, Blount says. This requires a lot of genome debugging, similar to what is done to computer codes. One team was able to combine several chromosomes into a single cell, and they survived and reproduced, demonstrating the mechanism for bringing them together. Blount says that constructing the genome—and knowing when a cell does not function as expected due to one change or another—has revealed fundamental information about the biology of the genome. For example, the team identified sequences in genes that halted a key process in the cell and led to mitochondrial dysfunction, which is linked to some human diseases.