Study Supports Distant Relationship Between Archaea and Bacteria in Tree of Life
Published:01 Mar.2022 Source:ELife
The analysis adds to an ongoing debate about how much the archaeal domain diverges from the bacterial domain and shines a light on the limitations of conventional methods for estimating the evolutionary path of ancient organisms. Together with Bacteria and Eukarya, the Archaea make up the three domains of the tree of life. Originally, it was thought that Archaea were a type of Bacteria, typified by their ability to live in extreme environments. But the use of molecular data to reconstruct phylogenetic trees and advances in genetic sequencing have transformed our understanding of the diversity of these organisms and their relationship with Bacteria and Eukarya.
In the tree of life, a long branch length between organisms corresponds to a greater degree of genetic change. Researchers studying the evolutionary history of the Archaea and Bacteria have estimated branch length by studying differences between a core set of essential genes encoding cellular machinery involved in producing proteins and processing genetic information. But recently, researchers used an expanded set of genetic markers from Bacteria and Archaea to estimate the genetic distance between the two domains and proposed a much shorter branch length -- that is, that the two domains were more closely related.