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The hologenome theory of evolution proposes that evolutionary forces acting at the level of an individual organism (e.g., a single plant or animal) are instead acting on the "holobiont" - the inherent community of a host plus all of its symbiotic microbes. As selection operates on phenotypes, classic individual selection is effectively selection on the holobiont. Consequently, the collective genomes of the holobiont form a "hologenome". Variation in the hologenome encodes variation in phenotypes upon which evolutionary forces such as selection or neutrality can operate. Although there is a rich literature on binary host–microbe symbioses, the hologenome theory distinguishes itself by including the vast symbiotic complexity inherent in macroscopic individuals. The development of the theory and current expansions are summarized in an open access platform.〔“Bordenstein, S.R. and K.R. Theis. 2015. Host biology in light of the microbiome: Ten principles of holobionts and hologenomes. PLOS Biology” http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.1002226#pbio.1002226.ref017〕 ==The Origin of the Hologenome Theory== In September 1994, Richard Jefferson first articulated the Hologenome Theory of Evolution, at a presentation at Cold Spring Harbor Laboratory, at a Symposium "A Decade of PCR", an published by Cold Spring Harbor Laboratory Press as a video series.〔Number 6 in a series of 7 VHS recordings, 'A Decade of PCR: Celebrating 10 Years of Amplification,' released by Cold Spring Harbor Laboratory Press, 1994. ISBN 0-87969-473-4. http://www.cshlpress.com/default.tpl?..〕〔https://www.youtube.com/watch?v=pgL3rmZL9P0〕 The term hologenome, coined by Jefferson at the Cold Spring Harbor Symposium, is derived from the Ancient Greek ὅλος (hólos, “whole”),〔https://en.wiktionary.org/wiki/holo-〕 and explicitly acknowledged that a multi-cellular organism's capabilities and fitness would be encoded by the entire suite of genomes - mostly microbial - that constituted the organism in the environment in which selection occurs. At the CSH Symposium and earlier, the unsettling number and diversity of microbes that were being discovered through the powerful tool of PCR-amplification of 16S ribosomal RNA genes was exciting, but confusing interpretations in diverse studies. A number of speakers referred to microbial contributions to mammalian or plant DNA samples as 'contamination'. In his lecture, Jefferson argued that these were likely not contamination, but rather essential components of the samples that reflected the actual genetic composition of the organism being studied, and that the logic of the organism's performance and capabilities would be embedded only in the hologenome. Observations on the ubiquity of microbes in plant and soil samples as well as laboratory work on molecular genetics of vertebrate-associated microbial enzymes informed this assertion (citations needed). In January 1997, the hologenome theory was extended,〔Jefferson, Richard A et al.. (1997). Molecular genetics of the ''E. coli gus'' operon: Medical and evolutionary implications for glucuronide and xenobiotic metabolism. 14th Congress of the South African Society of Biochemistry and Molecular Biology in Grahamstown, South Africa. http://dx.doi.org/10.5281/zenodo.22796〕 informed by further work on the molecular genetics of enteric microbial glucuronide metabolism at Cambia, to propose a central role of microbially-mediated hormone modulation (MHM) as an essential component of multi-cellularity and vertebrate biology. This led Jefferson to coin the term Ecotherapeutics, or ecological therapeutics, stating that a major route to improved performance of animals or plants would be through the adjustment of microbial populations and their genetic capabilities (microbiota often now called the (microbiomes), a field he called hologenetics. In 2008, Eugene Rosenberg and Ilana Zilber-Rosenburg independently developed the hologenome theory of evolution.〔“Zilber-Rosenberg and Eugene Rosenberg. 2008. Role of microorganisms in the evolution of animals and plants: the hologenome theory of evolution, FEMS Microbiology Reviews” http://onlinelibrary.wiley.com/doi/10.1111/j.1574-6976.2008.00123.x/full〕 This theory was originally based on the pair’s observations of Vibrio shiloi-mediated bleaching of the coral Oculina patagonica; and since its first introduction, the theory has been promoted as a fusion of Lamarckism and Darwinism and expanded to all of evolution, not just that of corals. The history of the development of the hologenome theory and the logic undergirding its development was the focus of a cover article by Carrie Arnold in New Scientist in January, 2013 〔“Creator of Species, The Hologenome, a New View of Evolution” https://www.newscientist.com/article/mg21728992-000-the-hologenome-a-new-view-of-evolution/〕 (Brucker and Bordenstein (2013) ) re-invigorated the idea of the hologenome theory of evolution using Nasonia wasps and their associated gut bacteria. This publication has formed the basis of the recent resurgence in proponents for the hologenome theory of evolution. However, (criticisms ) of this publication state that Brucker and Bordenstein (2013) do not disentangle the effects of (lethality ) from discordance between host-microbiome relations. As such, the hologenome theory of evolution awaits strong experimental support. In 2015, (Seth R. Bordenstein ) and (Kevin R. Theis ) outlined a conceptual framework that aligns with pre-existing theories in biology and serves as a roadmap for hypothesis-driven, experimentally validated research on holobionts and their hologenomes.〔 They discuss questions and critiques, show how neutral and selective processes are applicable to the intellectual framework, and discuss the future questions worthy of attention. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Hologenome theory of evolution」の詳細全文を読む スポンサード リンク
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