Have Researchers Created Synthetic Life at the J. Craig Venter Institute?

Researchers often insert a gene or two into an organism in order to make it do something unique. For example, researchers inserted the insulin gene into bacteria in order to make them produce human insulin. However, researchers at the J. Craig Venter Institute in Rockville, MD, have now created organisms that contain a completely synthetic genome (1). This synthetic genome was designed by computer, resulting in the "first self-replicating species ...whose parent is a computer," as stated by Dr. Venter, the lead scientist on this project.

In essence, the JCVI scientists took the genome of one bacterial species, M. mycoides, synthesized it from scratch, and then transplanted it into a different bacterial species, M. capricolum. The DNA was synthesized as a series of cassettes, or pieces, spanning roughly 1,080 bases (the chemical units that make up DNA) each. These cassettes were then painstakingly assembled together and slowly input into the M. capricolum species.

The JVCI researchers also included several "watermarks" in the synthetic genome. Because DNA contains introns, which are non-expressed spans of DNA, as well as exons, which are expressed spans of DNA, much of the code can be altered without affecting the final organism. Also, the four bases of the DNA code- A,C,G, and T- can combine into triplets to code for 20 amino acids (the chemical units of which protein is composed), as well as start and stop instructions for gene expression. These amino acids are designated by single alphabetical letters; for example, tryptophan is designated by the letter W. Thus, by using the amino acid "alphabet," the JCVI researchers were able to insert sequences of DNA that were specifically designed to spell out the names of study authors, project contributors, web addresses, and even include quotations from James Joyce and Richard Feynman. Such engineering helped clarify that the M. capricolum genome is completely synthetic and not a product of natural bacterial growth and replication.

Over one million total bases were inserted into M. capricolum. The final result was a bacterial cell that originated from M. capricolum, but behaved like and expressed the proteins of M. mycoides. This synthetic M. mycoides bacterium was also able to self-replicate, a fundamental quality of life.

The demonstration that completely synthetic genomes can be used to start synthetic life promises other exciting discoveries and technologies. For example, photosynthetic algae could be transplanted with genomes that would enable these organisms to produce biofuel (2). In fact, the ExxonMobil Research and Engineering Company has already worked out an agreement with Synthetic Genomics, the company the helped fund the JCVI research team, to start just such a project.

While some researchers agree that the technical feat of the JCVI team is astounding, detractors point to the difficulty of creating more complicated organisms "from scratch (3)." Other researchers point to the fact that some biofuels are already being produced by microorganisms via the genetic engineering of only a handful of genes. And Dr. David Baltimore, a leading geneticist at CalTech, has countered the significance of the work performed by the JCVI research team, stating that its lead researcher, Dr. Venter, "...has not created life, only mimicked it."

Resources:

1. JCVI Team Creates Functional Microbe Controlled By Synthetic Genome http://www.genomeweb.com/jcvi-team-creates-functional-microbe-controlled-synthetic-genome

2. Synthetic Genomics' Exxon Biofuel Pact Worth Up to $300M http://www.genomeweb.com/synthetic-genomics-exxon-biofuel-pact-worth-300m

3. Researchers Say They Created a 'Synthetic Cell'http://www.nytimes.com/2010/05/21/science/21cell.html