Help with inheritence.

[Nick Thompson]

Dear Friamers,

Everything that you-all are having me read  undermines the notion of natural selection.  But it does so by undermining genetic inheritance, the idea that because of genetic material passed from parent to offspring, offspring will differentially resemble.  I would have thought that of all the premises on which natural selection was based, the premise of family resemblance was the most secure.  I have two questions, Does complexity have an alternative theory of inheritance?  Does complexity have an evolutionary theory in which inheritance plays not significant part?

The full text of my rumination on this subject follows:

            It has become a standard critique  contra the neo-Darwinist synthesis  that it is based on an unrealistic, over-simplified, and perhaps ideologically based view of molecular genetics and development.   Books by Margulis, Caporale, Elldredge, Gould, and others emphasize the great complexity of the events that take place in the creation of the gamete genome, in the growth and development of the cells subsequent to fertilization, and in the day-to-day production of protein products by the bodies cells.  Some authors scoff at what they call the “bean-bag” genetics of neo-Darwinist and its gratuitous assumption that the genome consists of  a set of mutually independent, randomly reassorting heritable units.  The critique cannot be ignored:  The simple fact of chromosomes would seem to render such a conception absurd, even if one ignored  the recent discoveries of high levels of interaction among elements of  the nuclear genome and between that genome and the mitochondrial genome during cell division.
 
But exactly how is the above critique a critique of Darwinism.  Darwin’s theory is stated in the form of a hypothetical, a series of conditions which if met lead to adaptation and evolution.  We are thus led, by affirming the consequent, to the conclusion that these conditions are the cause of adaptation and evolution.  The conditions are:
 
(1)If  the reproductive potential of the members of a species is greatly in excess of the capacity of their worlds to support them
 
AND
 
(2) The members of this species vary in the possession of traits
 
AND
 
(3) Those traits are heritable (i.e., they are possessed differentially by the offspring of individuals that bear them)
 
AND
 
(4) some of these traits offer an advantage in the struggle for existence implied by (1)
 
THEN
 
(5)  traits of the type mentioned in (4) will in time come to characterize the species producing adaptation of the species to the conditions of its existence.  This process, applied to many species, will in time produce evolution, since evolution is just (on my account) the fact that over history,  different species have tended to adapt to their different conditions of existence.  
 
            Like all cumulative chains of premises, natural selection theory is a logical chain which depends on ALL of its elements  for its logical success.  In other words, if any of the 4 premises above is false, than natural selection as understood by Darwin cannot occur.  Which of the premises of natural selection does the developmentalist attack.  Surely not the Malthusian Premise, Premise (1).  Nor also the variational premise (2) nor the reproductive advantage premise (4).    The developmental critique is in fact an attack on the inheritance premise.  But the inheritance premise is the only one of the four that is NOT a hypothetical.  It is often said that Darwin’s explanation of inheritance was very bad, and got worse as he elaborated it through the several editions of the Origin.  But his knowledge of the FACTS of inheritance was very secure:  Darwin knew from close personal experience and avid reading that inheritance of traits from parents to offspring was a possibility. And a century of research in breeding and hybridization in plants and animals has not diminished our confidence that (at least) some traits can be differentially represented in parents and offspring.   For the developmental critique to succeed in its attempt to undermine Darwinism, it must do so by undermining not the theory of inheritance, but the fact of inheritance, and that fact would seem to be the most secure of Darwin’s premises.
 
            True, undermining the fact of inheritance would have a devastating effect on natural selection theory.  If natural selection is to work, then the parents have to serve, in effect, as representations of the offspring.  It must be true that decisions to breed or not to breed parents, based on their phenotype, must be reflected in the phenotypes of the offspring in the next generation.  Any developmental process that interferes with this representation from parental to offspring generation, interferes with natural selection.  Mutation interferes with natural selection.  Dominance and epistasis interfere with natural selection.  Genomic imprinting interferes with natural selection.  Horizontal transfer of genes from other organisms would interfere with natural selection.  Environmental muting or triggering of traits interferes with natural selection.  In fact, to the extent that any mechanism interferes with the isomporphism between variations in the parental generation and variations in the offspring generation, that mechanism interferes with natural selection.  It does so only because it interferes with inheritance.  
 
            So let is grant for the moment that the main challenge of developmentalists for natural selection theory is a challenge against Mendelism, not a challenge against Darwinism.  Does complexity theory have anything to offer to mitigate this challenge.  Is there a complexity variant of inheritance theory?
 
 
 


Nicholas S. Thompson
Professor of Psychology and Ethology
Clark University
[hidden email]
http://home.earthlink.net/~nickthompson/
[hidden email]
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[Russell Standish]

I'm not entirely sure what you mean by "Is there a complexity theory
of evolution without inheritance", but I know of no evolutionary
process studied in complex systems research that doesn't have
inheritance.

Consider an arbitrary irreversible process in a quantum multiverse
setting. Since quantum processes are reversible (unitary),
irreversibility comes about through the differentiation of the
observed "worlds". We have a process that is evolutionary by
Lewontin's 3 criteria:

1) Variation of succession states (through differentiation)
2) Selection (via observer selection, or "anthropic selection")
3) Inheritance (via continuity of the underlying quantum dynamics)

I have not attempted to analyse the case if the Many Worlds
Interpretation were not true, but being an "interpretation" it
shouldn't matter in some sense. So I'm lead to the conclusion that any
arbitrary irreversible process is "evolutionary", which by a curious
twist of fate was exactly what the term "evolution" meant pre-Darwin.

                                   Cheers

On Tue, Jan 25, 2005 at 02:04:56PM -0700, Nicholas Thompson wrote:
> Dear Friamers,
>
> Everything that you-all are having me read  undermines the notion of natural selection.  But it does so by undermining genetic inheritance, the idea that because of genetic material passed from parent to offspring, offspring will differentially resemble.  I would have thought that of all the premises on which natural selection was based, the premise of family resemblance was the most secure.  I have two questions, Does complexity have an alternative theory of inheritance?  Does complexity have an evolutionary theory in which inheritance plays not significant part?
>

--
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----------------------------------------------------------------------------
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UNSW SYDNEY 2052                     Fax   [phone] (")
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[Carl Tollander-2]

Nick,

I have not yet understood why hyperplasticity or dynamism in a genome
must necessarily interfere with inheritance.  It certainly may mediate
it. An applied complexity practitioner might find it reasonable to talk
about the robustness of a gene network relative to the non-canonical
regulatory and genetic transfer mechanisms you speak of.  Under some
circumstances these mechanisms might even reinforce inheritance.  My own
view (which I don't think is particularly radical anymore) is that
genes probably get expressed relative to the network environments they
find themselves in (which they may in their turn have a hand in
creating).  These notions (e.g. robustness of expresssion in the face
of regulatory or network variability) do not seem to me to be
antagonistic to inheritance, rather, they challenge and expand our
notions of what 'selection' is and means when we can no longer guarantee
1:1 mappings between groups of traits and gene groups or vice-versa.

I don't think I would have a problem with the idea of
that-which-is-inherited being somehow vetted through some sort of
genomic or epigenetic dynamics.  You might feel better considering
that those dynamics may be responsive to the same environment in which
the macro-scale selection occurs.

Caveat: All this blowing bubbles in the standard model is by way of
finding some theory to help us write some interesting (and yes, useful)
programs that may illuminate some larger issues about complex systems.
We're not necessarily saying earth works this way.
Or that it should.  Yet.

Carl

Nicholas Thompson wrote:

>
>
> Dear Friamers,
>  
> Everything that you-all are having me read  undermines the notion of
> natural selection.  But it does so by undermining genetic inheritance,
> the idea that because of genetic material passed from parent to
> offspring, offspring will differentially resemble.  I would have thought
> that of all the premises on which natural selection was based, the
> premise of family resemblance was the most secure.  I have two
> questions, Does complexity have an alternative theory of
> inheritance?  Does complexity have an evolutionary theory in which
> inheritance plays not significant part?
>  
> The full text of my rumination on this subject follows:
>  
>
>             It has become a standard critique  contra the neo-Darwinist
> synthesis  that it is based on an unrealistic, over-simplified, and
> perhaps ideologically based view of molecular genetics and
> development.   Books by Margulis, Caporale, Elldredge, Gould, and others
> emphasize the great complexity of the events that take place in the
> creation of the gamete genome, in the growth and development of the
> cells subsequent to fertilization, and in the day-to-day production of
> protein products by the bodies cells.  Some authors scoff at what they
> call the ?bean-bag? genetics of neo-Darwinist and its gratuitous
> assumption t hat the genome consists of  a set of mutually independent,
> randomly reassorting heritable units.  The critique cannot be ignored:
>  The simple fact of chromosomes would seem to render such a conception
> absurd, even if one ignored  the recent discoveries of high levels of
> interaction among elements of  the nuclear genome and between that
> genome and the mitochondrial genome during cell division.
>
>  
>
> But exactly how is the above critique a critique of Darwinism.  Darwin?s
> theory is stated in the form of a hypothetical, a series of conditions
> which if met lead to adaptation and evolution.  We are thus led, by
> affirming the consequent, to the conclusion that these conditions are
> the cause of adaptation and evolution.  The conditions are:
>
>  
>
> (1)If  the reproductive potential of the members of a species is greatly
> in excess of the capacity of their worlds to support them
>
>  
>
> AND
>
>  
>
> (2) The members of this species vary in the possession of traits
>
>  
>
> AND
>
>  
>
> (3) Those traits are heritable (i.e., they are possessed differentially
> by the offspring of individuals that bear them)
>
>  
>
> AND
>
>  
>
> (4) some of these traits offer an advantage in the struggle for
> existence implied by (1)
>
>  
>
> THEN
>
>  
>
> (5)  traits of the type mentioned in (4) will in time come to
> characterize the species producing adaptation of the species to the
> conditions of its existence.  This process, applied to many species,
> will in time produce evolution, since evolution is just (on my account)
> the fact that over history,  different species have tended to adapt to
> their different conditions of existence.
>
>  
>
>             Like all cumulative chains of premises, natural selection
> theory is a logical chain which depends on ALL of its elements  for its
> logical success.  In other words, if any of the 4 premises above is
> false, than natural selection as understood by Darwin cannot occur.  
> Which of the premises of natural selection does the developmentalist
> attack.  Surely not the Malthusian Premise, Premise (1).  Nor also the
> variational premise (2) nor the reproductive advantage premise (4).    
> The developmental critique is in fact an att ack on the inheritance
> premise.  But the inheritance premise is the only one of the four that
> is NOT a hypothetical.  It is often said that Darwin?s explanation of
> inheritance was very bad, and got worse as he elaborated it through the
> several editions of the Origin.  But his knowledge of the FACTS of
> inheritance was very secure:  Darwin knew from close personal experience
> and avid reading that inheritance of traits from parents to offspring
> was a possibility. And a century of research in breeding and
> hybridization in plants and animals has not diminished our confidence
> that (at least) some traits can be differentially represented in parents
> and offspring.   For the developmental critique to succeed in its
> attempt to undermine Darwinism, it must do so by undermining not the
> theory of inheritance, but the fact of inheritance, and that fact would
> seem to be the most secure of Darwin?s premises.
>
>  
>
>             True, undermining the fact of inheritance would have a
> devastating effect on natural selection theory.  If natural selection is
> to work, then the parents have to serve, in effect, as representations
> of the offspring.  It must be true that decisions to breed or not to
> breed parents, based on their phenotype, must be reflected in the
> phenotypes of the offspring in the next generation.  Any developmental
> process that interferes with this representation from parental to
> offspring generation, interferes with natural selection.  Mutation
> interferes with natural selection.  Do minance and epistasis interfere
> with natural selection.  Genomic imprinting interferes with natural
> selection.  Horizontal transfer of genes from other organisms would
> interfere with natural selection.  Environmental muting or triggering of
> traits interferes with natural selection.  In fact, to the extent that
> any mechanism interferes with the isomporphism between variations in the
> parental generation and variations in the offspring generation, that
> mechanism interferes with natural selection.  It does so only because
> */it interferes with inheritance/*.
>
>  
>
>             So let is grant for the moment that the main challenge of
> developmentalists for natural selection theory is a challenge against
> Mendelism, not a challenge against Darwinism.  Does complexity theory
> have anything to offer to mitigate this challenge.  Is there a
> complexity variant of inheritance theory?
>
>  
>
>  
>
>  
>  
>  
> Nicholas S. Thompson
> Professor of Psychology and Ethology
> Clark University
> [hidden email] <mailto:[hidden email]>
> http://home.earthlink.net/~nickthompson/
> [hidden email] <mailto:[hidden email]>
>  
>
>
> ------------------------------------------------------------------------
>
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