Although scientists may not have come close to cataloging all the different kinds of life on the planet, genetics pioneer Craig Venter is pressing ahead with his plans to create biology version 2.0. Venter is at the forefront of the new field of synthetic biology, in which scientists try to create all new organisms out of their component genetic parts: “We’re moving from reading the genetic code to writing it” [Pittsburgh Post-Gazette], Venter has said. Now, he and his colleagues have taken the next step towards synthetic life.
In a study published in Science, the researchers explain how they took the genome from the bacterium Mycoplasma mycoides and transferred it to a yeast cell, where established genetic engineering techniques allow for easier tinkering. After altering the genome in several key ways, they transplanted it into the hollowed out shell of a different bacterial species, Mycoplasma capricolum. The breakthrough came when the altered genome “booted up” and began instructing its host bacterium to produce colonies of M. mycoides.Â
That success will help researchers overcome a stubborn obstacle that has prevented the creation of a made-from-scratch life form. Last year, Venter’s team created a synthetic bacterial genome by stitching together pieces of synthesized DNA. To build a synthetic organism, however, researchers will have to transplant that synthetic genome into a cell and have it successfully reboot the cell. But that last step has proved problematic. The synthetic genome was assembled in yeast, which means it lacked some of the molecular markings characteristic of bacteria. Researchers discovered that without those markings, the host bacterium viewed the transplanted genome as a foreign invader and destroyed it [Technology Review]. In the new study, the researchers added chemical markings called methyl tags to the M. mycoides genome while it was in the yeast cell, permitting the genome to sneak past the host bacterium’s defenses.
