Lateral Gene Transfer and the Annealing Model of the Universal Ancestor

Question

Article: https://www.pnas.org/content/pnas/95/12/6854.full.pdf

The author proposes that lateral gene transfer can explain some of the evidence that is discordant with the traditional universal ancestor model. Analyze the role of lateral gene transfer at three different stages along the path of evolution. Use this statement from the author to describe the three stages:

“Evolution at the subcellular level can be viewed as a bridge between modern organismal evolution and the much earlier evolution that involved 'organic' chemicals in an abiotic world.”

Answer 1

The author of the article proposes that lateral gene transfer (LGT) can help explain some of the evidence that is inconsistent with the traditional universal ancestor model of evolution. LGT is the transfer of genetic material from one organism to another organism that is not its offspring. The author describes three stages where LGT may have played a role in evolution, using the following statement: “Evolution at the subcellular level can be viewed as a bridge between modern organismal evolution and the much earlier evolution that involved 'organic' chemicals in an abiotic world.”

The first stage where LGT may have played a role is in the early evolution of life, when organic chemicals in the abiotic world were starting to form complex systems that eventually led to the first living organisms. The transfer of genetic material from one system to another could have played a role in the formation of these complex systems.

The second stage is the evolution of the universal ancestor, which is the hypothetical organism from which all life on Earth is descended. The traditional view is that this organism was a single cell that gave rise to all life through vertical descent, meaning that its genetic material was passed down through generations. However, LGT could have also played a role in the evolution of the universal ancestor, with genetic material being transferred horizontally between different organisms.

The third stage is the evolution of modern organisms. LGT is known to occur in modern organisms and can play a significant role in their evolution, allowing for the acquisition of new genetic material that can confer new traits or functions.

Overall, the author suggests that LGT is an important factor to consider in understanding the evolution of life, particularly at the subcellular level, and that it may have played a significant role in the early stages of life's evolution as well as in the evolution of modern organisms.