+++
title = "Xenobiology"
slug = "xenobiology"
description = "Xenobiology builds life on non-standard chemistry: XNAs, expanded genetic alphabets, synthetic amino acids. The Raëlian canon describes no such chemistry."
template = "wiki-page.html"
toc = true

[extra]
editorial_pass = "2026-05"
claim_type = "direct"
core_claim_ids = ["woh-claim-0074", "woh-claim-0065", "woh-claim-0047", "woh-claim-0067"]
core_versions = { woh-claim-0074 = "0.1.1", woh-claim-0065 = "0.1.0", woh-claim-0047 = "0.1.0", woh-claim-0067 = "0.1.0" }
category = "Science & Technology"
entry_type = "concept"
summary = "Xenobiology is the branch of synthetic biology that builds organisms and biological systems on chemistry outside the standard set used by terrestrial life: synthetic genetic polymers (XNAs), expanded genetic alphabets, and organisms dependent on non-standard amino acids. Much of the field is motivated by biosafety, the idea of a 'genetic firewall' between engineered and natural life. An older sense of the word names the biology of hypothetical extraterrestrial life. The Raëlian canon describes the life the Elohim made as synthesized from terrestrial chemical components and interfertile with its makers, and nowhere describes non-standard biochemistry."
alternative_names = ["xeno-biology", "synthetic xenobiology", "xénobiologie (French)", "Xenobiologie (German)"]
timeline = ["age-of-aquarius"]
see_also = [
    { title = "Life Engineering", path = "wiki/life-engineering", description = "The umbrella entry: genetic engineering, synthetic biology, synthetic genomics, and xenobiology, with the field's research programmes." },
    { title = "Synthetic Biology", path = "wiki/synthetic-biology", description = "The parent discipline whose design-build-test approach xenobiology extends to the chemistry of life." },
    { title = "Synthetic Genomics", path = "wiki/synthetic-genomics", description = "Whole-genome design and synthesis, the sister field that works within standard biochemistry." },
    { title = "Astrobiology", path = "wiki/astrobiology", description = "The science of life in the universe, which absorbed the older 'biology of alien life' sense of xenobiology." },
    { title = "Pantropy", path = "wiki/pantropy", description = "Adapting life to other worlds, which the canon contemplates for engineered humanoids (TBWTT-4:61)." },
    { title = "Terraforming", path = "wiki/terraforming", description = "Adapting worlds to life, the converse of pantropy." },
    { title = "Cosmic Competition", path = "wiki/cosmic-competition", description = "The canon's humanities on other worlds, about whose biochemistry it is silent." },
    { title = "Cosmic Chain", path = "wiki/cosmic-chain", description = "The sequence of created and creating civilizations within which the canon places Earth's humanity." },
]
references = [
    { id = "the-book-which-tells-the-truth", locator = "TBWTT-1:61; 2:2; 2:16; 2:27; 2:55; 3:42; 3:279; 4:49; 4:61; 7:4; 7:23 (French base text)" },
    { id = "extraterrestrials-took-me-to-their-planet", locator = "ETTMTTP-2:30; 2:33; 3:23 (French base text)" },
    { id = "lets-welcome-the-extraterrestrials", locator = "LWTE-1:148–149 (Raël's commentary: chemical components and the molecular 'alphabet')" },
    { id = "genesis", locator = "Genesis 2:7 (the man formed from the dust of the ground), as read in LWTE-1:148" },
    { title = "The farther, the safer: a manifesto for securely navigating synthetic species away from the old living world", author = "Philippe Marlière", date = "2009", url = "https://doi.org/10.1007/s11693-009-9040-9" },
    { title = "Xenobiology: A new form of life as the ultimate biosafety tool", author = "Markus Schmidt", date = "2010", url = "https://doi.org/10.1002/bies.200900147" },
    { title = "Synthetic genetic polymers capable of heredity and evolution", author = "Vitor B. Pinheiro et al.", date = "2012", url = "https://doi.org/10.1126/science.1217622" },
    { title = "A semi-synthetic organism with an expanded genetic alphabet", author = "Denis A. Malyshev et al.", date = "2014", url = "https://doi.org/10.1038/nature13314" },
    { title = "Biocontainment of genetically modified organisms by synthetic protein design", author = "Daniel J. Mandell et al.", date = "2015", url = "https://doi.org/10.1038/nature14121" },
    { title = "Hachimoji DNA and RNA: A genetic system with eight building blocks", author = "Shuichi Hoshika et al.", date = "2019", url = "https://doi.org/10.1126/science.aat0971" },
    { title = "Is there a common chemical model for life in the universe?", author = "Steven A. Benner, Alonso Ricardo, Matthew A. Carrigan", date = "2004", url = "https://doi.org/10.1016/j.cbpa.2004.10.003" },
    { id = "creation-of-a-bacterial-cell-controlled-by-a-chemically-synthesized-genome", locator = "the 2010 synthesized-genome cell, the registered landmark of design-build-test biology" },
    { id = "crick-orgel-directed-panspermia", locator = "Icarus 19 (1973): deliberate seeding of life by an advanced civilization" },
    { id = "crick-life-itself", locator = "Crick's fuller statement of directed panspermia and his own assessment of its speculative standing" },
]

[extra.infobox]
type = "Branch of synthetic biology; in an older sense, the biology of hypothetical extraterrestrial life"
etymology = "Greek *xénos* ('stranger, foreign') + *biología*; in its current sense popularised by Markus Schmidt (2010)"
principal_programmes = "Xeno-nucleic acids (XNAs); unnatural base pairs and expanded genetic alphabets; non-canonical amino acids and recoded genetic codes; synthetic auxotrophy for biocontainment"
landmarks = "Marlière's manifesto (2009); Schmidt's biosafety programme (2010); heritable and evolvable XNAs (Pinheiro et al., 2012); a semi-synthetic organism with a six-letter genetic alphabet (Malyshev et al., 2014); synthetic auxotrophs (Mandell et al., 2015); eight-letter hachimoji DNA (Hoshika et al., 2019)"
in_the_canon = "The canon describes created life as synthesized from terrestrial chemical components, in its creators' image and interfertile with them. It describes no non-standard biochemistry, for Earth's life, for the Elohim, or for other worlds"
distinguished_from = "Astrobiology/exobiology (the study of life beyond Earth); synthetic genomics (genome design within standard biochemistry); pantropy (adapting organisms to other environments, whatever their chemistry)"
+++

**Xenobiology** is the branch of [synthetic biology](../synthetic-biology/) that
builds organisms and biological systems on chemistry outside the standard set
used by terrestrial life: genetic polymers other than DNA and RNA, genetic
alphabets with more than four letters, and proteins that depend on amino acids
outside the twenty standard ones. Much of the field is motivated by biosafety,
the aim of a "genetic firewall" that would keep engineered organisms unable to
exchange genes with, or survive among, natural ones.

The word has an older and looser second sense, the biology of hypothetical
extraterrestrial life, which overlaps with *exobiology* and is now largely
absorbed by [astrobiology](../astrobiology/). This entry treats the synthetic
sense as primary. The Raëlian canon bears on xenobiology chiefly through what it
does not say. It describes the life the Elohim made on Earth as synthesized from
terrestrial chemical components and nowhere describes a non-standard
biochemistry. It also describes that life as able to bear children with its
makers, a property xenobiology's organisms are designed to lack (see
[life engineering](../life-engineering/)).

## Etymology and the two senses

The word joins Greek *xénos*, "stranger" or "foreign," to *biology*. Its older
use belongs to the mid-twentieth-century vocabulary for the possible biology of
other worlds. The geneticist Joshua Lederberg proposed *exobiology* for that
study in 1960, and *xenobiology* has been used informally in the same sense. In
that sense the word asks what alien organisms might be made of and how they
might work.

The current scientific sense was fixed around 2009–2010. The French synthetic
biologist Philippe Marlière published in 2009 a manifesto, "The farther, the
safer," arguing that synthetic organisms should be moved chemically away from
"the old living world," so that their distance from natural biochemistry would
itself serve as a safeguard. The Austrian biosafety researcher Markus Schmidt, in
a 2010 paper in *BioEssays* titled "Xenobiology: A new form of life as the
ultimate biosafety tool," popularised the name in this sense and gave the field its
guiding image, the genetic firewall. On this programme an organism whose genetic material
uses a chemistry that natural cells cannot read, copy, or supply would be
contained by its own biochemistry.

The two senses meet at one question: which features of terrestrial biochemistry
are required of any life, and which belong only to the lineage that happens to
have evolved on Earth. Laboratory xenobiology approaches that question from the
synthetic side, by building alternatives and testing whether they work.

## The synthetic-biology field

The field's research programmes fall into a few families. The
[Life Engineering](../life-engineering/) entry describes them alongside the
other engineering disciplines; this section gives the landmark results.

**Synthetic genetic polymers.** In 2012 Vitor Pinheiro, Philipp Holliger, and
colleagues at the MRC Laboratory of Molecular Biology in Cambridge reported in
*Science* that several **xeno-nucleic acids** (XNAs), information-carrying
polymers built on backbones other than the ribose or deoxyribose of RNA and DNA,
could store genetic information and be copied and evolved under laboratory
selection, using engineered polymerases that write XNA from DNA templates and
read it back. The result showed that heredity and evolution are not tied to the
two natural nucleic acids.

**Expanded genetic alphabets.** In 2014 Denis Malyshev, Floyd Romesberg, and
colleagues at the Scripps Research Institute reported in *Nature* a
**semi-synthetic organism**: a strain of *Escherichia coli* that maintained and
replicated an unnatural base pair, d5SICS–dNaM, alongside the natural A–T and
G–C pairs, giving its DNA a six-letter alphabet. In 2019 Shuichi Hoshika, Steven
Benner, and colleagues at the Foundation for Applied Molecular Evolution in
Florida reported **hachimoji** ("eight letters") DNA and RNA, a genetic system in
which four synthetic nucleotides join the four natural ones. The hachimoji
system was demonstrated in the test tube rather than in living cells; it formed
regular double helices and could be transcribed into RNA.

**Synthetic auxotrophy.** In 2015 Daniel Mandell, George Church, and colleagues at
Harvard Medical School reported in *Nature* strains of *E. coli* with a recoded
genetic code whose essential proteins had been redesigned to require a synthetic
amino acid that does not occur in nature. Deprived of it, the bacteria could not survive.
This is the genetic-firewall idea in working form: containment by dependence on
a chemistry only the laboratory can supply.

The common result of these programmes is that parts of the standard chemistry of
terrestrial life (four nucleotide bases, two nucleic acids, twenty standard amino
acids, a near-universal genetic code) can be replaced or extended: in the test
tube for whole genetic systems, and in living cells for individual components.
No complete alternative chemistry has been shown to sustain an organism.
For mainstream biology this bears on the history of life and on the design of
safer engineered organisms. It carries no implication about how terrestrial
life came to have the chemistry it has, and the corpus draws none (see
"Discipline of the reading" below).

## The extraterrestrial sense

In its second sense xenobiology is the biology of life elsewhere, whatever that
life may be made of. Scientific discussion of the question now takes place
within astrobiology. The chemist Steven A. Benner and colleagues, in a 2004
review titled "Is there a common chemical model for life in the universe?",
surveyed which features of terrestrial biochemistry might be general to any life
and which might differ. Benner later led the hachimoji work, which
illustrates how the two senses of the word have converged in practice:
synthetic alternatives built in the laboratory serve as test cases for what
alien biochemistry could be. The [Astrobiology](../astrobiology/) entry covers
this science and the corpus's relation to it.

## In the primary sources

The canon's statements on the material of created life are few, and they are
reports: the dictated messages of *The Book Which Tells the Truth* (1974) and
*Extra-Terrestrials Took Me to Their Planet* (1975), and Raël's own commentary in
*Let's Welcome the Extra-terrestrials* (1979). Quotations below are from the
French base text.

{% claim(type="direct", id="woh-claim-0074") %}The canon describes the life the
Elohim made on Earth as synthesized from chemistry: plant cells created « à
partir de rien d'autre que des produits chimiques » ("from nothing other than
chemical products," TBWTT-2:16), after earlier work on their home world on
« cellules vivantes en éprouvettes » ("living cells in test tubes," TBWTT-2:2).{% end %}
Raël's commentary reads Genesis 2:7, where God forms the man from the dust of the
ground with the Hebrew potter's verb *yāṣar*, in the same terms: the creator
« a pris un peu des composants chimiques que l'on trouve dans la terre et ils
les a combinés scientifiquement » ("took a little of the chemical components
found in the earth and combined them scientifically," LWTE-1:148).

The messages report likeness and compatibility. Humanity was made « à notre
image », and « la ressemblance est frappante » ("the resemblance is striking,"
TBWTT-2:27); the creators could « s'accoupler avec les filles des hommes » and
have « des enfants exceptionnels » with them (TBWTT-2:55). The same likeness
extends to other worlds: « les hommes créent d'autres hommes, semblables à
eux-mêmes, sur d'autres mondes » ("men create other men, similar to themselves,
on other worlds," TBWTT-3:279). On two other planets there are beings
« semblables aux hommes et créés par les mêmes créateurs » (TBWTT-4:49), and
the universe holds « une infinité de mondes habités par des êtres de type
humanoïde » (TBWTT-7:23). The messages also report
divergence. The Elohim's atmosphere and Earth's are each unbreathable for the
other (TBWTT-1:61; 3:42), and the speaker breathes « un air différent du vôtre »
("an air different from yours," TBWTT-7:4).

{% claim(type="direct", id="woh-claim-0074") %}One passage states a forward plan
that is the canon's own version of [pantropy](../pantropy/): when a planet ceases
to be habitable, a civilization must either move or undertake « la création
d'une forme de vie humanoïde adaptée à un autre monde … Si le milieu ne peut
s'adapter aux hommes, il faut créer un homme adapté au milieu » ("the creation of
a humanoid form of life adapted to another world … If the environment cannot
adapt to men, one must create a man adapted to the environment," TBWTT-4:61),
for example « une autre race d'hommes vivant dans une atmosphère totalement
différente ».{% end %} The difference the passage names is physiological, an
atmosphere. Nothing in it concerns genetic chemistry.

On heredity the messages stay at the level of a plan: the cell carries « le plan
physique et intellectuel de l'être » (ETTMTTP-2:30), and the body forms according
to the plan defined at conception by « les gènes du mâle et de la femelle »
(ETTMTTP-2:33).

{% claim(type="direct", id="woh-claim-0074") %}The canon nowhere describes
non-standard biochemistry, alternative genetic chemistries, or the molecular
makeup of the Elohim or of life on other worlds. The dictated messages use no
vocabulary of DNA, nucleotides, or amino acids; their only genetic term is the
« gènes » of ETTMTTP-2:33, which names no chemistry.{% end %} The absence is an
omission: it neither affirms nor denies a universal biochemistry.

### Raël's alphabet gloss

In his 1979 commentary, in his own voice and not as dictated message, Raël adds
a gloss on the unity of terrestrial life. Every living being on Earth, he writes,
was made by the Elohim « à partir d'une "brique" de base, une structure
moléculaire composée d'atomes judicieusement assemblés » ("from a basic 'brick,'
a molecular structure composed of judiciously assembled atoms"): « une sorte
d'alphabet dont chaque lettre serait un atome, et qui composerait le code
génétique de chaque espèce vivante … les lettres de l'alphabet seraient toujours
les mêmes » ("a sort of alphabet, each letter of which would be an atom, making
up the genetic code of each living species … the letters of the alphabet would
always be the same"). Species then reproduce « le code génétique du premier
exemplaire de leur espèce qui a été fabriqué par les Elohim » (LWTE-1:149). The
English rendering in the project digitization omits the final clause, « qui a
été fabriqué par les Elohim » ("which was made by the Elohim"), which attributes
the first exemplar of each species to the creators.

The gloss is Raël's illustration, and its chemistry is loose. In biochemistry
the letters of the genetic code are nucleotide bases, each a molecule of many
atoms. The gloss's point, that all terrestrial life shares one set of building
blocks arranged in different orders, corresponds to the near-universal genetic
code of mainstream biology; its atom-for-letter analogy does not.

## In the Wheel of Heaven reading

{% claim(type="inferred", id="woh-claim-0065") %}The corpus reads humanity's
acquisition of life-engineering capability (genetic engineering, synthetic
biology, synthetic genomics) as the framework's most concrete predicted
convergence: the canon describes the creation in engineering terms and charges
its creations to do the same work in time, « créer ailleurs d'autres humanités,
scientifiquement » ("to create other humanities elsewhere, scientifically,"
ETTMTTP-3:23).{% end %} The registered landmark of that trajectory is the 2010
bacterial cell controlled by a chemically synthesized genome. Xenobiology is not
one of the disciplines the reading names, and the convergence yields the
availability of a mechanism and nothing more. That life can now be engineered,
in standard or non-standard chemistry, is no evidence that life on Earth was
engineered, and the scientists who do the work are enlisted for nothing.

Set beside the canon's account, the contrast is in the reported features. The
canon's created life is made from the chemistry of the planet it lives on, in
the image of its makers and able to bear children with them. Xenobiology's
organisms are made deliberately strange, so that they cannot mix with natural
life. The canon's own engineered humanoids of TBWTT-4:61 are adapted to a
different atmosphere; the passage leaves their chemistry unstated, and the
corpus assigns them none.

{% claim(type="framework", id="woh-claim-0047") %}Per the canon, Earth's humanity
is one of several humanities the Elohim created on several worlds.{% end %} The
canon gives the biology of those humanities no content beyond their likeness to
their creators, and the corpus does not supply one: whether they share Earth's
biochemistry is a question the sources leave open.

{% claim(type="inferred", id="woh-claim-0067") %}In science's own taxonomy the
Elohim hypothesis is an instance of directed panspermia, the possibility Francis
Crick and Leslie Orgel described in 1973, of life on Earth deliberately sown by
an advanced civilization.{% end %} The category supplies a place for the
hypothesis among scientific possibilities; it is no evidence for it, and neither
astrobiology nor xenobiology is enlisted for the framework.

### Discipline of the reading

This entry draws no design argument from biochemistry. The shared chemistry of
terrestrial life is not read as a design signature, and the contingency of that
chemistry, which xenobiology's working alternatives make visible, is not read as
a mark that separates designed life from evolved life. The corpus's position in
the design-inference debate, including its statement that no biological
evidence currently discriminates the two, is set out in the
[Intelligent Design](../intelligent-design/) entry and the Explainer
[*The Signature and the Designers*](/articles/the-signature-and-the-designers/).

## Alternatives and critical views

Several objections bear on the canon layer and on the corpus's reading of it.

- **Silence is not denial.** A text addressed in 1973 to a lay reader had no
  occasion to specify molecular chemistry. Reading the absence of non-standard
  biochemistry as a positive report of standard biochemistry over-reads an
  omission.
- **"In our image" is morphological.** Likeness to the creators, and the
  similarity of other humanities to theirs, may report bodily form and moral
  standing rather than molecular identity. Only the interfertility report
  (TBWTT-2:55) bears on genetic compatibility, and it concerns the Elohim and
  Earth's humanity alone.
- **The gloss belongs to its era.** Raël's 1979 alphabet restates the
  popular-science picture of a universal genetic code current in the 1970s,
  loosely (atoms for nucleotides). It reports the commentator's science
  education, not content from the messages.
- **The convergence as era projection.** The canon's engineering vocabulary may
  reflect its authorship in the decade recombinant DNA arrived, so that the
  "predicted convergence" is the era's ambient biotechnological ambition read
  back as foresight.
- **Feasibility is cheap.** Once a technology can imitate a mythic act, every
  such myth becomes "feasible." The availability of a mechanism selects the
  framework no more than it selects any other creation story.
- **Category comfort.** Directed panspermia is itself marginal. Crick, in *Life
  Itself* (1981), set the idea out at length while acknowledging its speculative
  standing, and situating the hypothesis within it borrows respectability from a
  slot science keeps as a curiosity.

## Distinguished from adjacent concepts

- **Astrobiology and exobiology** study life beyond Earth, whatever its chemistry.
  Laboratory xenobiology builds alternative chemistries on Earth.
- **[Synthetic genomics](../synthetic-genomics/)** designs and synthesizes whole
  genomes, so far within the standard four-letter chemistry.
- **[Pantropy](../pantropy/)** adapts organisms to environments other than their
  native one. It is defined by the environment, not by the chemistry, and the
  canon's version (TBWTT-4:61) specifies an atmosphere only.
- **[Terraforming](../terraforming/)** adapts a planet to existing life, the
  converse of pantropy. TBWTT-4:61 names relocation to another planet as the
  alternative to adapted humanoids.