Less is more: less is more. This is the philosophy that guides synthetic biology, the futuristic discipline that aims to recreate life from scratch, using synthetic components. A fundamental step in this direction consists in being able to develop microorganisms in the laboratory with an artificial genome reduced to the bare minimum, stripped of all superfluous functions but still capable of supporting survival and reproduction. This goal was claimed to have been achieved a few years ago, only to later realize that the minimal bacteria had stunted growth. The researchers, therefore, had to get back to work, armed with algorithms and test tubes, to really arrive at the result: bacteria of the genus Mycoplasma which, despite having a minimum set of genes, are able to divide, giving rise to daughter cells of uniform shape and size.
The work, just published in the magazine Cell by the pioneer of synthetic biology Craig Venter, identifies the virtuous compromise between miniaturization and efficiency in a genome composed of 480 genes, seven more than the model of synthetic bacterium presented in 2016 by the same institute, the «J. Craig Venter Institute »of San Diego. Compared to the old version, called JCVI-syn3.0, the new one is able to replicate better in vitro, forming beautiful colonies, thanks to its slightly enriched genetic endowment.
A lot to learn
Less is better, therefore, as long as you do not also eliminate the indispensable. When Elizabeth Strychalski of the US National Institute of Standards and Technology and colleagues discovered the replication flaws in Model 3.0, they retraced their steps, adding genes in different combinations and testing the effects under the microscope. Some of the seven reintroduced genes were known to play a role in cell division, but the others came as a surprise. In fact, about one-third of the genes in the minimal set for life were the result of unknown function, demonstrating that we still have a great deal to learn about the basics of life and its evolution.
Studying the minimal genome is a way to think about what the primordial cells that appeared in the mists of time on Earth must have been. But this line of research also has great application potential. In the future, synthetic microbes like these could be used as biofactories to produce drugs and biofuels. In practice, it is a question of redesigning “natural” bacteria by reducing them to minimal operating systems, which are agile and versatile at the same time. Without all the complications that evolutionary history has left to natural organisms, minimal cells could be optimal candidates for the role of mini-production plants.
March 29, 2021 (change March 30, 2021 | 07:26)