The first step toward building a mouse from synthetic DNA

Scientists have successfully created a small part of the DNA needed to build a mouse from scratch. It's just a step on on the long road to synthetic life, but in the short term their breakthrough could prevent genetic disease.

Previously the researchers, at the Venter Institute, synthesized an entire bacterial genome. That genome was functional: The researchers were able to implant it in a yeast bacteria, which replicated the synthetic DNA.

This new work on the mouse genome is much more ambitious than the bacterial genome. Ultimately it could lead to a process where scientists throw a few DNA strands into a mix of enzymes and reagents, incubate them at 50 degrees C, and wind up with a wriggly little mouse in less than a week.

But we're not there yet. That's why the researchers started small, building only the part of the mouse genome that's in mouse mitochondria, an organelle in cells that generates energy. There are a number of genetic diseases caused by mutations in mitochondrial genomes, so researchers are hopeful that their work could result in a way to replace faulty DNA in humans suffering from one of these inherited conditions.

They also worked on a problem that plagues synthetic biologists: How do you detect errors in your synthetic DNA? Obviously you don't want to build an organism whose DNA has errors in it, but building and then sequencing DNA is difficult and expensive. The researchers figured out a way to automate DNA code checking, which involves knitting the genome together from very small sequences that have been cloned and error-checked inside E. coli bacteria.

So what's the upshot? When will you have your synthetic, superpowered mouse - or your synthetic mitochondrial genome to cure a genetic disease? Probably not for a while. Researchers say this is just a proof-of-concept, and the genome they created wasn't functional - though it was error-free. Still, don't be surprised if you hear about completely synthetic mice - built by humans from the nucleotides up - running around in labs in about ten years.

Illustration by Harry Campbell

Read the full scientific paper in Nature (via Nature News).