Four-billion-year-old genetic code reconstructed by OSU scientist

Tuesday, August 9, 2016

An Oklahoma State University microbiologist and a colleague have reported progress in understanding the evolutionary origin of the genetic code used by all known cells. The scientists reconstructed the genetic code of the last universal common ancestor (LUCA), believed by some scientists to be the origin of all life on Earth.

Wouter Hoff, with OSU’s Department of Microbiology and Molecular Genetics, and Peter van der Gulik, with CWI, the Netherland’s national research institute for mathematics and computer science, published their findings in the journal PLoS ONE. The evolutionary origin of the genetic code has remained a scientific puzzle since its original discovery in the 1960s, which was a seminal breakthrough in understanding the molecular basis of life.

LUCA is the proposed single-cell organism that gave rise to the current three domains of life: Archaea, Bacteria, and Eucarya that includes plants and animals. It is believed LUCA lived four billion years ago and may have developed in the extreme conditions surrounding deep sea vents where magma rises to the surface. The properties of LUCA and its possible resemblance to present day organisms are currently attracting intense scientific attention and mainstream news coverage. An influential, but hotly debated, notion is that modern Archaea living in extreme environments most resemble LUCA.

“Our reconstruction of LUCA’s genetic code reveals that the evolution of the set of transfer RNA molecules that are at the center of the genetic code was already almost complete in LUCA,” said Hoff. “Our work reveals that the set of transfer RNA molecules in LUCA closely resembles that in present day Archaea. In this respect, the primordial character referred to in the name of Archaea seems very appropriate.”

To obtain their results, Hoff and van der Gulik used recent genomic and biochemical data in combination with a largely ignored but central biochemical regularity in the genetic code.

“While many questions regarding the origin of the genetic code remain to be addressed, this publication makes a clear step in elucidating part of the evolutionary development of this process that is so important for all living organisms,” Hoff said.

Visit http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0158342 to read the article.