An estimation of minimal genome size required for life

Itaya, Mitsuhiro

doi:10.1016/0014-5793(95)00233-y

Cited by 132 publications

(67 citation statements)

References 13 publications

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“…These numbers are in agreement with the computational and experimental determinations of the minimal genome size necessary to sustain a functional cell (Itaya 1995;Mushegian and Koonin 1996;Pál et al 2006). However, the ancestral reconstruction of a minimal gene set in LUCA approaches are influenced by several factors.…”

Section: And What About Luca?supporting

confidence: 83%

Early Microbial Evolution: The Age of Anaerobes

Martin

Sousa

2015

Cold Spring Harb Perspect Biol

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In this article, the term "early microbial evolution" refers to the phase of biological history from the emergence of life to the diversification of the first microbial lineages. In the modern era (since we knew about archaea), three debates have emerged on the subject that deserve discussion: (1) thermophilic origins versus mesophilic origins, (2) autotrophic origins versus heterotrophic origins, and (3) how do eukaryotes figure into early evolution. Here, we revisit those debates from the standpoint of newer data. We also consider the perhaps more pressing issue that molecular phylogenies need to recover anaerobic lineages at the base of prokaryotic trees, because O 2 is a product of biological evolution; hence, the first microbes had to be anaerobes. If molecular phylogenies do not recover anaerobes basal, something is wrong. Among the anaerobes, hydrogen-dependent autotrophs-acetogens and methanogenslook like good candidates for the ancestral state of physiology in the bacteria and archaea, respectively. New trees tend to indicate that eukaryote cytosolic ribosomes branch within their archaeal homologs, not as sisters to them and, furthermore tend to root archaea within the methanogens. These are major changes in the tree of life, and open up new avenues of thought. Geochemical methane synthesis occurs as a spontaneous, abiotic exergonic reaction at hydrothermal vents. The overall similarity between that reaction and biological methanogenesis fits well with the concept of a methanogenic root for archaea and an autotrophic origin of microbial physiology.

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Section: And What About Luca?supporting

confidence: 83%

Early Microbial Evolution: The Age of Anaerobes

Martin

Sousa

2015

Cold Spring Harb Perspect Biol

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“…lethal genes (Itaya, 1995). It did not list the essential genes but only their proportion regarding to the total number of genes.…”

Section: Experimental Approachmentioning

confidence: 99%

Essential molecular functions associated with the circular code evolution

Ahmed

Frey

Michel

2010

Journal of Theoretical Biology

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“…It was found in the 1990s that the number of truly essential genes of any organism might be quite small compared to its complete genome. For instance, some gene knock-out experiments have shown that the bacterium Bacillus subtilis might still do well with only ~300 genes left out of its original pool of ~4100 genes (Itaya 1995). Cross-species comparison of genomes via computational comparative genomics indicate that certain genes tend to be quite closely related across species.…”

Section: The 'Ancestral Organisms' and The Tree Of Life Before Themmentioning

confidence: 99%

Lifeness signatures and the roots of the tree of life

Malaterre

2010

Biol Philos

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Do trees of life have roots? What do these roots look like? In this contribution, I argue that research on the origins of life might offer glimpses on the topology of these very roots. More specifically, I argue (1) that the roots of the tree of life go well below the level of the commonly mentioned 'ancestral organisms' down into the level of much simpler, minimally living entities that might be referred to as 'protoliving systems', and (2) that further below, a system of roots gradually dissolves into non-living matter along several functional dimensions. In between non-living and living matter, one finds physico-chemical systems that I propose to characterize by a 'lifeness signature'. In turn, this 'lifeness signature' might also account for a diverse range of biochemical entities that are found to be 'less-than-living' yet 'more-than-nonliving'.

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An estimation of minimal genome size required for life

Cited by 132 publications

References 13 publications

Early Microbial Evolution: The Age of Anaerobes

Early Microbial Evolution: The Age of Anaerobes

Essential molecular functions associated with the circular code evolution

Lifeness signatures and the roots of the tree of life

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