Studies support the distant relationship between archaea and bacteria in the tree of life

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Scientists have found further evidence to support the idea that archaea and bacteria, two major areas of life, are distantly related because they are separated by long phylogenetic tree branches. The findings are reported in a study published today. eLife..

Analysis by the University of Bristol and international researchers has been added to the ongoing discussion of how archaeal domains diverge from bacterial domains, limiting conventional methods for estimating the evolutionary pathways of ancient organisms. Shine light on.

Archaea, along with bacteria and eukaryotes, make up three areas of the tree of life. Originally, archaea are a type of bacterium and were thought to be represented by their ability to live in extreme environments. However, using molecular data to reconstruct the phylogenetic tree, Gene sequencing It has changed our understanding of the relationship between the diversity of these organisms and bacteria and eukaryotes.

In the tree of life, the length of long branches between organisms corresponds to a greater degree of genetic change. Researchers studying the history of paleontology and bacterial evolution have branch lengths by studying the differences between core sets of essential genes that encode cellular mechanisms involved in protein production and processing of genetic information. Was estimated. But recently, researchers have used an extended set of genetic markers from bacteria and archaea to estimate the genetic distance between the two domains and suggest much shorter branch lengths. That is, the two domains were more closely related.

“this Recent works Lead author Edmund Moody, a PhD candidate at the Bristol Department of Life Sciences, explains: Core genes may not represent the entire ancient genome, and second, there may be more suitable genes than previously realized for investigating the history of early evolution. It is possible and may improve the accuracy and accuracy of these estimates. “

To investigate these issues, Moody and colleagues looked at the evolutionary history of the extended 381 gene. marker We reassessed the set, and the marker gene set used in the previous analysis. They discovered several functions of the extended marker set, such as interdomain gene transfer and paralogous genes. These are genes that have evolved through duplication and encode proteins with similar but non-identical functions. “Our data suggest that the inclusion of marker genes with such characteristics can artificially shorten the branches that separate archaea and bacterial domains,” co-author Tara Mahendra Raja. The doctor says. Candidate for NIOZ in the Netherlands.

Traditionally used genetic marker sets contain genes for many proteins that make up the ribosome, the cellular mechanism for translating DNA. It has been suggested that if ribosomal proteins experience an accelerated evolutionary period at any point in time, it may lead to artificially long phylogenetic tree branches. So the team compared a set of ribosome and nonribosomal genetic markers to make an estimate of branch length and found that they were similar.

Anja Spang, senior scientist and co-chief author of NIOZ, said: “These results do not support the hypothesis that ribosomal proteins evolved faster than non-ribosome genes, confirming that ribosomal proteins are useful markers of phylogeny. Both true Archaea-Bacteria. branch Archaeal length and diversity may be underestimated even in the best models today. “

“The discussion of these issues really speaks to the more general limitations of the current model. For example, it is clearly inadequate to make an early evolutionary or genetic diversity view based on a small set. am. geneTom Williams, co-chief author and associate professor of molecular evolution at the Bristol Department of Life Sciences, said: Method. Our study shows that new methods, including more realistic models of gene duplication, transmission, and loss, allow estimation of the evolution of the entire genome, taking into account the various evolutionary histories of individual gene families. Suggests that it may help solve some of the different views.

Njordarchaeota, a new candidate for a sister group of eukaryotes

For more information:
Edmund RR Moody et al, Estimating the deepest branch of the tree of life from ancient vertical evolution genes, eLife (2022). DOI: 10.7554 / eLife.66695

Journal information:

Quote: The study was obtained from on February 22, 2022 (February 22, 2022). ) Supports the distant relationship between archaea and bacteria

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Studies support the distant relationship between archaea and bacteria in the tree of life

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