Hello Syn

By Drs. David Niesel and Norbert Herzog, Medical Discovery News

We live in a wondrous time. We can 3D print almost anything including some human tissues. Biotechnology is revolutionizing the energy industry and personalized medicine has the promise of delivering individual treatments for heart disease and other major illnesses. And we can play God and create life! In fact we are up to version 3.0! Scientists have created a living bacterium with genetic information made from only chemicals in a test tube.

The focus of this current study was to determine the minimal essential genes for life for a microbial organism. The process used is called synthetic biology. The first synthetic organism JCVI syn 1.0 was created in 2010. Recently, improving on this process, scientists have created JCVI syn 3.0. This latest version has just 473 genes and of these over one third are ones we do not know what they do - only that they are essential to life. This has led to some excitement in that scientists want to understand these unknown genes and what they mean for life.

This team was led by the same scientists who sequenced the genome of the first free living bacterium - Haemophilus influenzae way back in 1995. This was ground breaking work that represented a real milestone in genomic research. In contrast to syn 3.0, this bacterium is mammoth having 1815 genes. The sequencing of this bacterial genome can be taken as the start of efforts to understand the minimum complement of genes that would allow life. The question became just how many genes and which ones are needed to produce a living organism?

How did they do this? Remember that genomes are constructed of a four letter alphabet of DNA - containing A, G, T, and C. For synthetic biology, these letters are linked together chemically in a test tube in the precise sequence to reconstruct the genes needed for a living organism. This is like typing out letters to form words and sentences but using chemical synthesis to link the letters (A, G, T, C) in the proper order. In the first step, sentences of this genetic code up to 1000 letters long are chemically synthesized. Next, these sentences are linked together to form 10,000 letter long sequences - sort of like paragraphs. Then, these are linked to form 100,000 letter long sequences - together these represent chapters. Finally, the handful of these long sequences are then linked together to form the genome to make a book. Then, using some genetic trickery, the completed genome is introduced into a bacterial cell that has had its own genome removed. The new synthetic genome reboots the bacterial cell and voila - a brand new type of bacterial cell that has never existed before with syn 3.0 as its genome.

In a clever and playful move, the designers have also added the equivalent of watermarks to the syn 3.0 genome sequence. Since the DNA is composed of chemical letters, the scientists have added their names and famous quotes embedded in the genetic code of syn 3.0.

Medical Discovery News is hosted by professors Norbert Herzog at Quinnipiac University, and David Niesel of the University of Texas Medical Branch. Learn more at www.medicaldiscoverynews.com.