First universal common ancestor

Last updated

The first universal common ancestor (FUCA) is a proposed non-cellular entity that is the earliest ancestor of the last universal common ancestor (LUCA) and its descendants, including every modern cell. [1] [2] FUCA would also be the ancestor of ancient sister lineages of LUCA, none of which have modern descendants. [2]

Contents

FUCA is thought to have been composed of progenotes, proposed ancient biological systems that would have used RNA for their genome and self-replication, in place of DNA. [3] [4] [5] By comparison, LUCA would have had a complex metabolism and genome with hundreds of genes and gene families. [1]

The now-extinct sister lineages descended from FUCA are thought to have horizontally transferred some of their genes into the genome of early descendants of LUCA. [2]

Origins

Long before the appearance of compartmentalized biological entities like FUCA, life had already began to organize itself and emerge in a pre-cellular era known as the RNA world. [3] The universal presence of both biological translation mechanism and genetic code in every biological systems indicates monophyly, a unique origin for all biological systems including viruses and cells. [1] [3]

FUCA would have been the first organism capable of biological translation, using RNA molecules to convert information into peptides and produce proteins. [1] This first translation system would have been assembled together with primeval, possibly error-prone genetic code. [1] FUCA would also be the first biological system to have genetic code. [6]

The development of FUCA likely took a long time. [1] FUCA was generated without genetic code, from the ribosome, [1] itself a system evolved from the maturation of a ribonucleoprotein machinery. [3] FUCA appeared when a proto-peptidyl transferase center started to first emerge, when RNA world replicators started to be capable to catalyze the bonding of amino acids into oligopeptides. [1]

The first genes of FUCA were most likely encoding ribosomal, primitive tRNA-aminoacyl transferases and other proteins that helped to stabilize and maintain biological translation. [6] These random peptides produced possibly bound back to the single strand nucleic acid polymers and allowed a higher stabilization of the system that got more robust and was further bound to other stabilizing molecules. [1] When FUCA had matured, its genetic code was completely established. [1]

FUCA was composed by a population of open-systems, self-replicating ribonucleoproteins. [3] With the arrival of these systems, began the progenote era. [3] These systems evolved into maturity when self-organization processes resulted in the creation of a genetic code. [3] This genetic code was for the first time capable to organize an ordered interaction between nucleic acids and proteins through the formation of a biological language. [3] This caused pre-cellular open systems to then start to accumulate information and self-organize, producing the first genomes by the assembly of biochemical pathways, which probably appeared in different progenote populations evolving independently. [3]

In the reduction hypothesis, where giant viruses evolved from primordial cells that became parasitic, viruses might have evolved after FUCA and before LUCA. [2]

Progenotes

Progenotes (also called ribocytes or ribocells) [7] [8] [9] are semi-open or open biological systems capable of performing an intense exchange of genetic information, before the existence of cells and LUCA. [4] [3] The term progenote was coined by Carl Woese in 1977, [10] around the time he introduced the concept of the three domains of life (bacteria, archaea, and eukaryotes) and proposed that each domain originated from a different progenote. [11] [12] The meaning of the term changed with time. In the 1980s, Doolittle and Darnell used the word progenote to designate the ancestor of all three domains of life, [13] now referred to as the last universal common ancestor (LUCA). [14]

The terms ribocyte and ribocell refer to progenotes as protoribosomes, primeval ribosomes that were hypothetical cellular organisms with self-replicating RNA but without DNA, [8] [15] and thus with a RNA genome instead of the usual DNA genome. [5] In Carl Woese's Darwinian threshold period of cellular evolution, the progenotes are also thought to have had RNA as informational molecule instead of DNA. [7]

The evolution of the ribosome from ancient ribocytes, self-replicating machines, into its current form as a translational machine may have been the selective pressure to incorporate proteins into the ribosome's self-replicating mechanisms, so as to increase its capacity for self-replication. [16] [17] Ribosomal RNA is thought to have emerged before cells or viruses, at the time of progenotes. [3]

Progenotes composed and were the descendants of FUCA, [3] and FUCA is thought to have organized the process between the initial organization of biological systems and the maturation of progenotes. [3] Progenotes were dominants in the Progenote age, the time where biological systems originated and initially assembled. [3] The Progenote age would have happened after the pre-biotic age of the RNA-world and Peptide-world but before the age of organisms and mature biological systems like viruses, bacteria and archaea. [3]

The most successful progenotes populations were probably the ones capable to bind and process carbohydrates, amino acids and other intermediated metabolites and co-factors. [3] In progenotes, compartmentalization with membranes was not yet completed and translation of proteins was not precise. Not every progenote had its own metabolism; different metabolic steps were present in different progenotes. Therefore, it is assumed that there existed a community of sub-systems that started to cooperate collectively and culminated in the LUCA. [7]

Ribocytes and viruses

In the eocyte hypothesis, the organism at the root of all eocytes may have been a ribocyte of the RNA-world. For cellular DNA and DNA handling, an "out of virus" scenario has been proposed: storing genetic information in DNA may have been an innovation performed by viruses and later handed over to ribocytes twice, once transforming them into bacteria and once transforming them into archaea. [18]

Similarly in viral eukaryogenesis, a hypothesis theorizing that eukaryotes evolved from a DNA Virus, ribocytes may have been an ancient host for the DNA virus. [19] As ribocytes used RNA to store their genetic info, [19] viruses may initially have adopted DNA as a way to resist RNA-degrading enzymes in the host ribocells. Hence, the contribution from such a new component may have been as significant as the contribution from chloroplasts or mitochondria. Following this hypothesis, archaea, bacteria, and eukaryotes each obtained their DNA informational system from a different virus. [20]

See also

Related Research Articles

<span class="mw-page-title-main">RNA</span> Family of large biological molecules

Ribonucleic acid (RNA) is a polymeric molecule that is essential for most biological functions, either by performing the function itself or by forming a template for the production of proteins. RNA and deoxyribonucleic acid (DNA) are nucleic acids. The nucleic acids constitute one of the four major macromolecules essential for all known forms of life. RNA is assembled as a chain of nucleotides. Cellular organisms use messenger RNA (mRNA) to convey genetic information that directs synthesis of specific proteins. Many viruses encode their genetic information using an RNA genome.

<span class="mw-page-title-main">RNA world</span> Hypothetical stage in the early evolutionary history of life on Earth

The RNA world is a hypothetical stage in the evolutionary history of life on Earth, in which self-replicating RNA molecules proliferated before the evolution of DNA and proteins. The term also refers to the hypothesis that posits the existence of this stage.

<span class="mw-page-title-main">Retrovirus</span> Family of viruses

A retrovirus is a type of virus that inserts a DNA copy of its RNA genome into the DNA of a host cell that it invades, thus changing the genome of that cell. After invading a host cell's cytoplasm, the virus uses its own reverse transcriptase enzyme to produce DNA from its RNA genome, the reverse of the usual pattern, thus retro (backwards). The new DNA is then incorporated into the host cell genome by an integrase enzyme, at which point the retroviral DNA is referred to as a provirus. The host cell then treats the viral DNA as part of its own genome, transcribing and translating the viral genes along with the cell's own genes, producing the proteins required to assemble new copies of the virus. Many retroviruses cause serious diseases in humans, other mammals, and birds.

<span class="mw-page-title-main">Carl Woese</span> American microbiologist (1928–2012)

Carl Woese was an American microbiologist and biophysicist. Woese is famous for defining the Archaea in 1977 through a pioneering phylogenetic taxonomy of 16S ribosomal RNA, a technique that has revolutionized microbiology. He also originated the RNA world hypothesis in 1967, although not by that name. Woese held the Stanley O. Ikenberry Chair and was professor of microbiology at the University of Illinois Urbana–Champaign.

<span class="mw-page-title-main">Ribozyme</span> Type of RNA molecules

Ribozymes are RNA molecules that have the ability to catalyze specific biochemical reactions, including RNA splicing in gene expression, similar to the action of protein enzymes. The 1982 discovery of ribozymes demonstrated that RNA can be both genetic material and a biological catalyst, and contributed to the RNA world hypothesis, which suggests that RNA may have been important in the evolution of prebiotic self-replicating systems.

Viral evolution is a subfield of evolutionary biology and virology that is specifically concerned with the evolution of viruses. Viruses have short generation times, and many—in particular RNA viruses—have relatively high mutation rates. Although most viral mutations confer no benefit and often even prove deleterious to viruses, the rapid rate of viral mutation combined with natural selection allows viruses to quickly adapt to changes in their host environment. In addition, because viruses typically produce many copies in an infected host, mutated genes can be passed on to many offspring quickly. Although the chance of mutations and evolution can change depending on the type of virus, viruses overall have high chances for mutations.

<span class="mw-page-title-main">Last universal common ancestor</span> Most recent common ancestor of all current life on Earth

The last universal common ancestor (LUCA) is the hypothesized common ancestral cell from which the three domains of life, the Bacteria, the Archaea, and the Eukarya originated. It is suggested to have been a "cellular organism that had a lipid bilayer and used DNA, RNA, and protein". The LUCA has also been defined as "a hypothetical organism ancestral to all three domains". The LUCA is the point or stage at which the three domains of life diverged from preexisting forms of life. The nature of this point or stage of divergence remains a topic of research.

Viral eukaryogenesis is the hypothesis that the cell nucleus of eukaryotic life forms evolved from a large DNA virus in a form of endosymbiosis within a methanogenic archaeon or a bacterium. The virus later evolved into the eukaryotic nucleus by acquiring genes from the host genome and eventually usurping its role. The hypothesis was first proposed by Philip Bell in 2001 and was further popularized with the discovery of large, complex DNA viruses that are capable of protein biosynthesis.

<span class="mw-page-title-main">Non-cellular life</span> Life that has no cellular structure

Non-cellular life, also known as acellular life, is life that exists without a cellular structure for at least part of its life cycle. Historically, most definitions of life postulated that an organism must be composed of one or more cells, but this is for some no longer considered necessary, and modern criteria allow for forms of life based on other structural arrangements.

<span class="mw-page-title-main">Gustavo Caetano-Anolles</span>

Gustavo Caetano-Anollés is Professor of Bioinformatics in the Department of Crop Sciences, University of Illinois at Urbana-Champaign. He is an expert in the field of evolutionary and comparative genomics.

<span class="mw-page-title-main">Virus</span> Infectious agent that replicates in cells

A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898, more than 11,000 of the millions of virus species have been described in detail. The study of viruses is known as virology, a subspeciality of microbiology.

<span class="mw-page-title-main">Prokaryote</span> Unicellular organism lacking a membrane-bound nucleus

A prokaryote is a single-cell organism whose cell lacks a nucleus and other membrane-bound organelles. The word prokaryote comes from the Ancient Greek πρό 'before' and κάρυον 'nut, kernel'. In the two-empire system arising from the work of Édouard Chatton, prokaryotes were classified within the empire Prokaryota. But in the three-domain system, based upon molecular analysis, prokaryotes are divided into two domains: Bacteria and Archaea. Organisms with nuclei are placed in a third domain, Eukaryota.

<span class="mw-page-title-main">Horizontal gene transfer in evolution</span> Evolutionary consequences of transfer of genetic material between organisms of different taxa

Horizontal gene transfer (HGT) refers to the transfer of genes between distant branches on the tree of life. In evolution, it can scramble the information needed to reconstruct the phylogeny of organisms, how they are related to one another.

Evolution of cells refers to the evolutionary origin and subsequent evolutionary development of cells. Cells first emerged at least 3.8 billion years ago approximately 750 million years after Earth was formed.

Numerous key discoveries in biology have emerged from studies of RNA, including seminal work in the fields of biochemistry, genetics, microbiology, molecular biology, molecular evolution and structural biology. As of 2010, 30 scientists have been awarded Nobel Prizes for experimental work that includes studies of RNA. Specific discoveries of high biological significance are discussed in this article.

<span class="mw-page-title-main">Eocyte hypothesis</span> Hypothesis in evolutionary biology

The eocyte hypothesis in evolutionary biology proposes that the eukaryotes originated from a group of prokaryotes called eocytes. After his team at the University of California, Los Angeles discovered eocytes in 1984, James A. Lake formulated the hypothesis as "eocyte tree" that proposed eukaryotes as part of archaea. Lake hypothesised the tree of life as having only two primary branches: prokaryotes, which include Bacteria and Archaea, and karyotes, that comprise Eukaryotes and eocytes. Parts of this early hypothesis were revived in a newer two-domain system of biological classification which named the primary domains as Archaea and Bacteria.

<span class="mw-page-title-main">Positive-strand RNA virus</span> Class of viruses in the Baltimore classification

Positive-strand RNA viruses are a group of related viruses that have positive-sense, single-stranded genomes made of ribonucleic acid. The positive-sense genome can act as messenger RNA (mRNA) and can be directly translated into viral proteins by the host cell's ribosomes. Positive-strand RNA viruses encode an RNA-dependent RNA polymerase (RdRp) which is used during replication of the genome to synthesize a negative-sense antigenome that is then used as a template to create a new positive-sense viral genome.

<span class="mw-page-title-main">Darwinian threshold</span> Period during the evolution of the first cells

Darwinian threshold or Darwinian transition is a term introduced by Carl Woese to describe a transition period during the evolution of the first cells when genetic transmission moves from a predominantly horizontal mode to a vertical mode. The process starts when the ancestors of the Last Universal Common Ancestor become refractory to horizontal gene transfer (HGT) and become individual entities with vertical heredity upon which natural selection is effective. After this transition, life is characterized by genealogies that have a modern tree-like phylogeny.

In virology, realm is the highest taxonomic rank established for viruses by the International Committee on Taxonomy of Viruses (ICTV), which oversees virus taxonomy. Six virus realms are recognized and united by specific highly conserved traits:

Virosphere was coined to refer to all those places in which viruses are found or which are affected by viruses. However, more recently virosphere has also been used to refer to the pool of viruses that occurs in all hosts and all environments, as well as viruses associated with specific types of hosts, type of genome or ecological niche.

References

  1. 1 2 3 4 5 6 7 8 9 10 Prosdocimi, Francisco; José, Marco V.; de Farias, Sávio Torres (2019), Pontarotti, Pierre (ed.), "The First Universal Common Ancestor (FUCA) as the Earliest Ancestor of LUCA's (Last UCA) Lineage", Evolution, Origin of Life, Concepts and Methods, Cham: Springer International Publishing, pp. 43–54, doi:10.1007/978-3-030-30363-1_3, ISBN   978-3-030-30363-1, S2CID   199534387, archived from the original on 2022-06-29, retrieved 2023-11-02
  2. 1 2 3 4 Harris, Hugh M. B.; Hill, Colin (2021). "A Place for Viruses on the Tree of Life". Frontiers in Microbiology. 11. doi: 10.3389/fmicb.2020.604048 . ISSN   1664-302X. PMC   7840587 . PMID   33519747.
  3. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 de Farias, Sávio Torres; Jose, Marco V.; Prosdocimi, Francisco (2021). "Is it possible that cells have had more than one origin?". Bio Systems. 202: 104371. doi:10.1016/j.biosystems.2021.104371. ISSN   1872-8324. PMID   33524470. Archived from the original on 2023-12-30. Retrieved 2024-02-23.
  4. 1 2 Woese, Carl (1998-06-09). "The universal ancestor". Proceedings of the National Academy of Sciences. 95 (12): 6854–6859. Bibcode:1998PNAS...95.6854W. doi: 10.1073/pnas.95.12.6854 . ISSN   0027-8424. PMC   22660 . PMID   9618502.
  5. 1 2 Lane N (2015). The Vital Question – Energy, Evolution, and the Origins of Complex Life . WW Norton. p.  77. ISBN   978-0-393-08881-6.
  6. 1 2 Prosdocimi, Francisco; Farias, Farias (2020). From FUCA To LUCA: A Theoretical Analysis on the Common Descent of Gene Families. doi:10.31080/ASMI.2020.03.0494 (inactive 31 January 2024). Retrieved 2023-11-02.{{cite book}}: CS1 maint: DOI inactive as of January 2024 (link)
  7. 1 2 3 José, Marco V.; Rêgo, Thais Gaudêncio; Farias, Sávio Torres de (2015-12-03). "A proposal of the proteome before the last universal common ancestor (LUCA)". International Journal of Astrobiology. 15 (1): 27–31. doi: 10.1017/S1473550415000464 . ISSN   1473-5504.
  8. 1 2 Yarus M (2002). "Primordial genetics: phenotype of the ribocyte". Annual Review of Genetics. 36: 125–51. doi:10.1146/annurev.genet.36.031902.105056. PMID   12429689.
  9. ↑ Forterre P, Krupovic M (2012). "The Origin of Virions and Virocells: The Escape Hypothesis Revisited". Viruses: Essential Agents of Life. pp. 43–60. doi:10.1007/978-94-007-4899-6_3. ISBN   978-94-007-4898-9.
  10. ↑ Woese, C. R.; Fox, G. E. (1977-09-20). "The concept of cellular evolution". Journal of Molecular Evolution. 10 (1): 1–6. doi:10.1007/BF01796132. ISSN   0022-2844. PMID   903983. S2CID   24613906. Archived from the original on 2023-11-08. Retrieved 2024-02-23.
  11. ↑ Woese CR, Fox GE (November 1977). "Phylogenetic structure of the prokaryotic domain: the primary kingdoms". Proceedings of the National Academy of Sciences of the United States of America. 74 (11): 5088–90. Bibcode:1977PNAS...74.5088W. doi: 10.1073/pnas.74.11.5088 . PMC   432104 . PMID   270744.
  12. ↑ Koonin, Eugene V (2014-03-01). "Carl Woese's vision of cellular evolution and the domains of life". RNA Biology. 11 (3): 197–204. doi:10.4161/rna.27673. ISSN   1547-6286. PMC   4008548 . PMID   24572480.
  13. ↑ Doolittle, W. F.; Darnell, J. E. (1986-03-01). "Speculations on the early course of evolution". Proceedings of the National Academy of Sciences. 83 (5): 1271–1275. Bibcode:1986PNAS...83.1271D. doi: 10.1073/pnas.83.5.1271 . ISSN   1091-6490. PMC   323057 . PMID   2419905.
  14. ↑ Weiss, Madeline C.; Preiner, Martina; Xavier, Joana C.; Zimorski, Verena; Martin, William F. (2018-08-16). "The last universal common ancestor between ancient Earth chemistry and the onset of genetics". PLOS Genetics. 14 (8): e1007518. doi: 10.1371/journal.pgen.1007518 . ISSN   1553-7390. PMC   6095482 . PMID   30114187.
  15. ↑ Forterre P, Krupovic M (2012). "The Origin of Virions and Virocells: The Escape Hypothesis Revisited". Viruses: Essential Agents of Life. pp. 43–60. doi:10.1007/978-94-007-4899-6_3. ISBN   978-94-007-4898-9.
  16. ↑ Root-Bernstein M, Root-Bernstein R (February 2015). "The ribosome as a missing link in the evolution of life". Journal of Theoretical Biology. 367: 130–158. doi: 10.1016/j.jtbi.2014.11.025 . PMID   25500179.
  17. ↑ Fox GE (September 2010). "Origin and Evolution of the Ribosome". Cold Spring Harb Perspect Biol. 2 (9): a003483. doi: 10.1101/cshperspect.a003483 . PMC   2926754 . PMID   20534711.
  18. ↑ Forterre P, Krupovic M (2012). "The Origin of Virions and Virocells: The Escape Hypothesis Revisited". In Witzany G (ed.). Viruses: Essential Agents of Life. pp. 43–60. doi:10.1007/978-94-007-4899-6_3. ISBN   978-94-007-4898-9.
  19. 1 2 Claverie, Jean-Michel (2006). "Viruses take center stage in cellular evolution". Genome Biology. 7 (6): 110. doi: 10.1186/gb-2006-7-6-110 . PMC   1779534 . PMID   16787527.
  20. ↑ Forterre, Patrick (March 2006). "Three RNA cells for ribosomal lineages and three DNA viruses to replicate their genomes: a hypothesis for the origin of cellular domain". Proceedings of the National Academy of Sciences of the United States of America. 103 (10): 3669–74. Bibcode:2006PNAS..103.3669F. doi: 10.1073/pnas.0510333103 . JSTOR   30048645. PMC   1450140 . PMID   16505372.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.