Xenobiology is the branch of synthetic biology that\nbuilds organisms and biological systems on chemistry outside the standard set\nused by terrestrial life: genetic polymers other than DNA and RNA, genetic\nalphabets with more than four letters, and proteins that depend on amino acids\noutside the twenty standard ones. Much of the field is motivated by biosafety,\nthe aim of a \"genetic firewall\" that would keep engineered organisms unable to\nexchange genes with, or survive among, natural ones.
\nThe word has an older and looser second sense, the biology of hypothetical\nextraterrestrial life, which overlaps with exobiology and is now largely\nabsorbed by astrobiology. This entry treats the synthetic\nsense as primary. The Raëlian canon bears on xenobiology chiefly through what it\ndoes not say. It describes the life the Elohim made on Earth as synthesized from\nterrestrial chemical components and nowhere describes a non-standard\nbiochemistry. It also describes that life as able to bear children with its\nmakers, a property xenobiology's organisms are designed to lack (see\nlife engineering).
\nThe word joins Greek xénos, \"stranger\" or \"foreign,\" to biology. Its older\nuse belongs to the mid-twentieth-century vocabulary for the possible biology of\nother worlds. The geneticist Joshua Lederberg proposed exobiology for that\nstudy in 1960, and xenobiology has been used informally in the same sense. In\nthat sense the word asks what alien organisms might be made of and how they\nmight work.
\nThe current scientific sense was fixed around 2009–2010. The French synthetic\nbiologist Philippe Marlière published in 2009 a manifesto, \"The farther, the\nsafer,\" arguing that synthetic organisms should be moved chemically away from\n\"the old living world,\" so that their distance from natural biochemistry would\nitself serve as a safeguard. The Austrian biosafety researcher Markus Schmidt, in\na 2010 paper in BioEssays titled \"Xenobiology: A new form of life as the\nultimate biosafety tool,\" popularised the name in this sense and gave the field its\nguiding image, the genetic firewall. On this programme an organism whose genetic material\nuses a chemistry that natural cells cannot read, copy, or supply would be\ncontained by its own biochemistry.
\nThe two senses meet at one question: which features of terrestrial biochemistry\nare required of any life, and which belong only to the lineage that happens to\nhave evolved on Earth. Laboratory xenobiology approaches that question from the\nsynthetic side, by building alternatives and testing whether they work.
\nThe field's research programmes fall into a few families. The\nLife Engineering entry describes them alongside the\nother engineering disciplines; this section gives the landmark results.
\nSynthetic genetic polymers. In 2012 Vitor Pinheiro, Philipp Holliger, and\ncolleagues at the MRC Laboratory of Molecular Biology in Cambridge reported in\nScience that several xeno-nucleic acids (XNAs), information-carrying\npolymers built on backbones other than the ribose or deoxyribose of RNA and DNA,\ncould store genetic information and be copied and evolved under laboratory\nselection, using engineered polymerases that write XNA from DNA templates and\nread it back. The result showed that heredity and evolution are not tied to the\ntwo natural nucleic acids.
\nExpanded genetic alphabets. In 2014 Denis Malyshev, Floyd Romesberg, and\ncolleagues at the Scripps Research Institute reported in Nature a\nsemi-synthetic organism: a strain of Escherichia coli that maintained and\nreplicated an unnatural base pair, d5SICS–dNaM, alongside the natural A–T and\nG–C pairs, giving its DNA a six-letter alphabet. In 2019 Shuichi Hoshika, Steven\nBenner, and colleagues at the Foundation for Applied Molecular Evolution in\nFlorida reported hachimoji (\"eight letters\") DNA and RNA, a genetic system in\nwhich four synthetic nucleotides join the four natural ones. The hachimoji\nsystem was demonstrated in the test tube rather than in living cells; it formed\nregular double helices and could be transcribed into RNA.
\nSynthetic auxotrophy. In 2015 Daniel Mandell, George Church, and colleagues at\nHarvard Medical School reported in Nature strains of E. coli with a recoded\ngenetic code whose essential proteins had been redesigned to require a synthetic\namino acid that does not occur in nature. Deprived of it, the bacteria could not survive.\nThis is the genetic-firewall idea in working form: containment by dependence on\na chemistry only the laboratory can supply.
\nThe common result of these programmes is that parts of the standard chemistry of\nterrestrial life (four nucleotide bases, two nucleic acids, twenty standard amino\nacids, a near-universal genetic code) can be replaced or extended: in the test\ntube for whole genetic systems, and in living cells for individual components.\nNo complete alternative chemistry has been shown to sustain an organism.\nFor mainstream biology this bears on the history of life and on the design of\nsafer engineered organisms. It carries no implication about how terrestrial\nlife came to have the chemistry it has, and the corpus draws none (see\n\"Discipline of the reading\" below).
\nIn its second sense xenobiology is the biology of life elsewhere, whatever that\nlife may be made of. Scientific discussion of the question now takes place\nwithin astrobiology. The chemist Steven A. Benner and colleagues, in a 2004\nreview titled \"Is there a common chemical model for life in the universe?\",\nsurveyed which features of terrestrial biochemistry might be general to any life\nand which might differ. Benner later led the hachimoji work, which\nillustrates how the two senses of the word have converged in practice:\nsynthetic alternatives built in the laboratory serve as test cases for what\nalien biochemistry could be. The Astrobiology entry covers\nthis science and the corpus's relation to it.
\nThe canon's statements on the material of created life are few, and they are\nreports: the dictated messages of The Book Which Tells the Truth (1974) and\nExtra-Terrestrials Took Me to Their Planet (1975), and Raël's own commentary in\nLet's Welcome the Extra-terrestrials (1979). Quotations below are from the\nFrench base text.
\n\nThe canon describes the life the\nElohim made on Earth as synthesized from chemistry: plant cells created « à\npartir de rien d'autre que des produits chimiques » (\"from nothing other than\nchemical products,\" TBWTT-2:16), after earlier work on their home world on\n« cellules vivantes en éprouvettes » (\"living cells in test tubes,\" TBWTT-2:2).\n\nRaël's commentary reads Genesis 2:7, where God forms the man from the dust of the\nground with the Hebrew potter's verb yāṣar, in the same terms: the creator\n« a pris un peu des composants chimiques que l'on trouve dans la terre et ils\nles a combinés scientifiquement » (\"took a little of the chemical components\nfound in the earth and combined them scientifically,\" LWTE-1:148).
\nThe messages report likeness and compatibility. Humanity was made « à notre\nimage », and « la ressemblance est frappante » (\"the resemblance is striking,\"\nTBWTT-2:27); the creators could « s'accoupler avec les filles des hommes » and\nhave « des enfants exceptionnels » with them (TBWTT-2:55). The same likeness\nextends to other worlds: « les hommes créent d'autres hommes, semblables à\neux-mêmes, sur d'autres mondes » (\"men create other men, similar to themselves,\non other worlds,\" TBWTT-3:279). On two other planets there are beings\n« semblables aux hommes et créés par les mêmes créateurs » (TBWTT-4:49), and\nthe universe holds « une infinité de mondes habités par des êtres de type\nhumanoïde » (TBWTT-7:23). The messages also report\ndivergence. The Elohim's atmosphere and Earth's are each unbreathable for the\nother (TBWTT-1:61; 3:42), and the speaker breathes « un air différent du vôtre »\n(\"an air different from yours,\" TBWTT-7:4).
\n\nOne passage states a forward plan\nthat is the canon's own version of pantropy: when a planet ceases\nto be habitable, a civilization must either move or undertake « la création\nd'une forme de vie humanoïde adaptée à un autre monde … Si le milieu ne peut\ns'adapter aux hommes, il faut créer un homme adapté au milieu » (\"the creation of\na humanoid form of life adapted to another world … If the environment cannot\nadapt to men, one must create a man adapted to the environment,\" TBWTT-4:61),\nfor example « une autre race d'hommes vivant dans une atmosphère totalement\ndifférente ».\n The difference the passage names is physiological, an\natmosphere. Nothing in it concerns genetic chemistry.
\nOn heredity the messages stay at the level of a plan: the cell carries « le plan\nphysique et intellectuel de l'être » (ETTMTTP-2:30), and the body forms according\nto the plan defined at conception by « les gènes du mâle et de la femelle »\n(ETTMTTP-2:33).
\n\nThe canon nowhere describes\nnon-standard biochemistry, alternative genetic chemistries, or the molecular\nmakeup of the Elohim or of life on other worlds. The dictated messages use no\nvocabulary of DNA, nucleotides, or amino acids; their only genetic term is the\n« gènes » of ETTMTTP-2:33, which names no chemistry.\n The absence is an\nomission: it neither affirms nor denies a universal biochemistry.
\nIn his 1979 commentary, in his own voice and not as dictated message, Raël adds\na gloss on the unity of terrestrial life. Every living being on Earth, he writes,\nwas made by the Elohim « à partir d'une \"brique\" de base, une structure\nmoléculaire composée d'atomes judicieusement assemblés » (\"from a basic 'brick,'\na molecular structure composed of judiciously assembled atoms\"): « une sorte\nd'alphabet dont chaque lettre serait un atome, et qui composerait le code\ngénétique de chaque espèce vivante … les lettres de l'alphabet seraient toujours\nles mêmes » (\"a sort of alphabet, each letter of which would be an atom, making\nup the genetic code of each living species … the letters of the alphabet would\nalways be the same\"). Species then reproduce « le code génétique du premier\nexemplaire de leur espèce qui a été fabriqué par les Elohim » (LWTE-1:149). The\nEnglish rendering in the project digitization omits the final clause, « qui a\nété fabriqué par les Elohim » (\"which was made by the Elohim\"), which attributes\nthe first exemplar of each species to the creators.
\nThe gloss is Raël's illustration, and its chemistry is loose. In biochemistry\nthe letters of the genetic code are nucleotide bases, each a molecule of many\natoms. The gloss's point, that all terrestrial life shares one set of building\nblocks arranged in different orders, corresponds to the near-universal genetic\ncode of mainstream biology; its atom-for-letter analogy does not.
\n\nThe corpus reads humanity's\nacquisition of life-engineering capability (genetic engineering, synthetic\nbiology, synthetic genomics) as the framework's most concrete predicted\nconvergence: the canon describes the creation in engineering terms and charges\nits creations to do the same work in time, « créer ailleurs d'autres humanités,\nscientifiquement » (\"to create other humanities elsewhere, scientifically,\"\nETTMTTP-3:23).\n The registered landmark of that trajectory is the 2010\nbacterial cell controlled by a chemically synthesized genome. Xenobiology is not\none of the disciplines the reading names, and the convergence yields the\navailability of a mechanism and nothing more. That life can now be engineered,\nin standard or non-standard chemistry, is no evidence that life on Earth was\nengineered, and the scientists who do the work are enlisted for nothing.
\nSet beside the canon's account, the contrast is in the reported features. The\ncanon's created life is made from the chemistry of the planet it lives on, in\nthe image of its makers and able to bear children with them. Xenobiology's\norganisms are made deliberately strange, so that they cannot mix with natural\nlife. The canon's own engineered humanoids of TBWTT-4:61 are adapted to a\ndifferent atmosphere; the passage leaves their chemistry unstated, and the\ncorpus assigns them none.
\n\nPer the canon, Earth's humanity\nis one of several humanities the Elohim created on several worlds.\n The\ncanon gives the biology of those humanities no content beyond their likeness to\ntheir creators, and the corpus does not supply one: whether they share Earth's\nbiochemistry is a question the sources leave open.
\n\nIn science's own taxonomy the\nElohim hypothesis is an instance of directed panspermia, the possibility Francis\nCrick and Leslie Orgel described in 1973, of life on Earth deliberately sown by\nan advanced civilization.\n The category supplies a place for the\nhypothesis among scientific possibilities; it is no evidence for it, and neither\nastrobiology nor xenobiology is enlisted for the framework.
\nThis entry draws no design argument from biochemistry. The shared chemistry of\nterrestrial life is not read as a design signature, and the contingency of that\nchemistry, which xenobiology's working alternatives make visible, is not read as\na mark that separates designed life from evolved life. The corpus's position in\nthe design-inference debate, including its statement that no biological\nevidence currently discriminates the two, is set out in the\nIntelligent Design entry and the Explainer\nThe Signature and the Designers.
\nSeveral objections bear on the canon layer and on the corpus's reading of it.
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