Informational genetics refers to the unification of Shannon's
information theory and genetics.
The unification of information theory and genetics was pioneered by G.
C. Williams. Some quotes ilustrate his perspective:
"In this book I use the term gene to mean 'that which segregates and recombines with appreciable
frequency'" - Williams, 1966, page 241.
"In evolutionary theory, a gene could be defined as
any hereditary information for which there is a favorable or
unfavorable selection bias equal to several or many times the rate of
endogenous change" - Williams 1966, page 25.
"A gene is not a DNA molecule; it is the transcribable
information coded by the molecule" - Williams 1992, page 11.
This view of genes as informational entities was subsequently
embraced by numerous theoretical biologists - and popularised
by writers such as Dawkins and Hull.
The specific definitions which Williams gives have some problems.
Defining a gene (or, strictly speaking, an allele) as something which
has an "appreciable frequency" results in novel mutations which occur
only once in the population being denied the status of genes.
Defining genes (or, strictly speaking, alleles) in terms of the
selection pressure on them doesn't seem right either. If an allele
happens to be neutral, surely it doesn't suddenly stop being an
Worse, these definitions conflict with each other. One mentions
selection, and the other mentions frequency. An allele can rise
in frequency for other reasons besides its selective benefit -
e.g. because of linkage to beneficial alleles present at other loci.
The reason Williams adopted these definitions appears to be
because he wanted his definition to address the issue of how big genes
Molecular geneticists sometimes define evolution in terms of
changes in allele frequencies. With such a definition, the issue
of how big alleles are can seem to be important.
However, these definitions introduce serious problems - so serious
that we must reject them as being terminally flawed.
Alleles should broadly map onto the idea of Mendelian
factors. Neither the strength of the selection pressure on them
nor their frequencies are relevant to this.
The key insight of Williams - that genes are informational - is very
At first glance some may regard this idea as trivially wrong.
Organisms inherit more than just information from their ancestors.
They inherit geographical location, their ecosystem, pathogens,
grandfather clocks, traditions - and all manner of other things.
However, if you look across multiple generations and ask what
actually persists over extended periods of time, the answer is
almost always some kind of digital information.
Grandfather clocks disintegrate, but digital patterns can live
forever. Digital information can be backed up and copied. It is
therefore potentially immortal - it can evade entropy and death. No
physical object can do the same. What evolves and changes over time is,
at its base, informational in nature.
Phenotypes may appear to persist overtime - however, they do
so as a consequence of the persistence of genetic information.
Dawkins originally used the term "gene" to refer to these persistent
informational entities. However, after a while, he came to regard the
term "gene" as too heavily overloaded - and so adopted the term
David Hull also began to use the term "replicator" in this context.
Hull defined a replicator as: "an entity that passes on its structure
largely intact in successive generations" - Hull, 1988.
Unfortunately, the actual condition for an information
carrying substrate to support an evolutionary process is that it is
capable of sustaining information transfer across multiple
generations. How much of its "structure" remains "largely intact" in
the process is not critical. Self-encrypting computer viruses
demonstrate one of the problems associated with Hull's definition.
The "replicator" terminology has several problems:
The term replicate has the implication of high-fidelity
copying. However, we know from information theory that information can
survive in relatively poor-fidelity copying systems - provided they
employ redundancy and error correction. This insight dates back to J.
von Neumann's paper: "Probabilistic logics and synthesis of reliable
organisms from unreliable components."
Also, the study of genes is genetics. And a collection of
genes is a genome. What is the study of replicators? And what do we
call a collection of replicators?
Adopting the replicator terminology requires us to reinvent parallel
copies of existing terminology. We see this has already happened in
terminology associated with cultural evolution. Memetics is
the study of memes. A memeplex is a collection of
memes. Sue Blackmore has proposed that we need additional
concepts, temes and presumably temetics - to deal
with inheritance mediated via machines. Should we also have renetics,
the study of replicators - and a rene - an individual replicating
In my view, this is all poor terminology. We have only one
fundamental entity here, and do not need multiple names for it.
The basic concept is that of inheritance.
The best way forwards is to abandon the replicator
terminology - and go back to the original vision of Williams
and Dawkins - by using the terms "gene", "genetics" and "genome".
Yes, these terms are overloaded, and yes,
that is a potential cause of confusion - but using them
really is the best way forwards for evolutionary biology.
Definition of Gene
Since Williams did not provide a viable definition of "gene" I propose
that a gene be defined as being "a small section of heritable
This avoids the problems the definitons of Williams - while dodging
the question of how big a gene is - an issue which I do not see any
way to address concisely enough to go into a short and snappy
The informational definiton of a gene faces another issue: it makes it
very clear that it is impossible to evade the conclusion that
human culture constitutes heritable information.
If you define genes as small bits of heritable information,
then ideas - and other cultural information - inevitably fits
Culture becomes a type of genetic information which simply happens to
be inherited in media other than DNA - and is passed down the
generation via pathways which are largely independent of DNA-based
Conventional discussions of whether a trait is genetic or cultural
turn into incomprehensible nonsense: culture is genetic - by
Some people's reaction to this is to reject this redefinition of the
term "gene" as flying in the face of common usage - and common sense.
However, in my view, the proper reaction is different. The idea that
culture is genetic information which happens not to be represented as
DNA represents a shift in perspective which contains deep insights.
Cultural evolution is not merely a process analogous to DNA
evolution. It is part of evolution. The new
replicators are not merely analogous to genes. They
are genes. Companies, religions, books, movies, etc do not just
evolve and change like living entities, they are
living entities. Culture becomes part of biology. Memes are
simply a type of gene that is not made of DNA.
Artificial Life enthusiasts have long derided definitions of
life, genes and biology that reference the
details of biochemistry - as carbon chauvanism. The belief
that genes are necessarily made of DNA is castigated as being
nucleic-acid centrism. Such ideas represent out-dated thinking,
which biologists have got to get over.
This absorption of cultural evolution into the mainstream of
evolutionary theory is long overdue.
As Dennett puts it:
Many Darwinians are anxious, a little uneasy, would
like to see some limits on just how far the Darwinism goes.
It's all right, you know. Spider webs? Sure, they are products of
evolution. The World Wide Web? Not so sure. Beaver dams, yes; Hoover
What do they think it is that prevents the products of human ingenuity
from being themselves fruits of the tree of life - and hence in some
sense obeying evolutionary rules?
Cultural evolution is evolution - according to modern
definitions of evolution:
Biological Evolution entails inherited changes in
populations of organisms, over a period of time, that lead to
differences among them.
- Monroe Strickberger, Evolution, 1996.
Nowhere does it say that inheritance must take place via DNA.
Strickberger goes on to put the case for cultural inheritance concisely:
In short, humans have two unique hereditary systems.
One is the genetic system that transfers biological information from
biological parent to offspring in the form of genes and chromosomes.
The other is the extragenetic system that transfers cultural
information from speaker to listener, from writer to reader, from
performer to spectator, and forms our cultural heritage.
- Monroe Strickberger, Evolution, 1996.
If it fails to embrace cultural evolution, evolutionary theory fails
to account for the origin and development of mankind - and also, of
course, the development of modern science and technology. That would
be a miserable failure - and a totally unnecessary one.
- G. C. Williams - Adaptation and Natural Selection - 1966
- G. C. Williams - Natural Selection: Domains, Levels, and Challenges - 1992
- Richard Dawkins - The Selfish Gene - 1976
- David Hull - Science as Process: An Evolutionary Account of the Social and Conceptual Development of Science - 1988
- Monroe Strickberger - Evolution - 1996