Article: Scientists shake Darwin's foundation -- chickens inherited parents' stress symptoms
Robert Karl Stonjek
symptoms
Evolutionary theory ever since Darwin is based on the assumption that
acquired traits, such as learnt modifications of behaviour, cannot be
inherited by the offspring. Now, a Swedish-Norwegian research group, led by
professor Per Jensen at Linköping university in Sweden, shows that chickens
can actually inherit behavioural modifications induced by stress in their
parents.
The scientists grew groups of chickens under stressful conditions, where a
randomly fluctuating day-night rhythm made access to food and resting
perches unpredictable. This caused a marked decrease in the ability of the
stressed birds to solve a spatial learning task. Remarkably, their offspring
also had a decreased learning ability, in spite of being kept under
non-stress conditions from the point of egg-laying. They were also more
competitive and grew faster than offspring of non-stressed birds.
To investigate whether there was any genetic basis for the effect, the
research group examined the expression levels of about 9000 genes in the
brain of the chickens. In birds exposed to stress, there was a number of
genes where the expression was either increased or decreased, and the same
genes were similarly affected in the offspring.
The results therefore demonstrate that both the changes in gene function and
the behavioural changes caused by stress were transferred to the offspring.
Both these effects were only seen in domesticated chickens, not in the
ancestor, the red junglefowl. The scientists therefore speculate that
domestication may have favoured animals which are able to affect the biology
of their offspring through genetic modifications.
The results offer new insights into how animal populations may be capable of
adaptation to stressful environments in evolutionary short times. This can
help explain both the rapid development of animals during domestication, and
evolutionary responses to changing conditions in nature.
Source: Linköping university
http://www.physorg.com/news95607862.html
Comment:
Lamarck...
Posted by
Robert Karl Stonjek
Bob Kolker
> Scientists shake Darwin's foundation -- chickens inherited parents' stress
> symptoms
>
> Evolutionary theory ever since Darwin is based on the assumption that
> acquired traits, such as learnt modifications of behaviour, cannot be
> inherited by the offspring. Now, a Swedish-Norwegian research group, led by
Cite please. Where did Darwin say or write this?
> professor Per Jensen at Linköping university in Sweden, shows that chickens
> can actually inherit behavioural modifications induced by stress in their
> parents.
That means stress somehow modifed the genes. Or maybe it is something
else and the researchers have incorrectly interpreted their data.
Bob Kolker
Tim Tyler
> Scientists shake Darwin's foundation -- chickens inherited parents' stress
> symptoms
>
> Evolutionary theory ever since Darwin is based on the assumption that
> acquired traits, such as learnt modifications of behaviour, cannot be
> inherited by the offspring. Now, a Swedish-Norwegian research group, led by
> professor Per Jensen at Linköping university in Sweden, shows that chickens
> can actually inherit behavioural modifications induced by stress in their
> parents.
To parody:
Scientists stressed pregnant chickens.
Their eggs were a fraction of the normal sire and the offspring were
screwed up, did not develop well and exhibited general stress responses.
Sensing a news story the scientists examined the expression
levels of about 9000 genes in the brain of the chickens, and
noticed that many of the stress-induced changes in the
offspring resembled those in the parents.
Certainly Darwin would never have thought of that.
--
__________
|im |yler http://timtyler.org/ t...@tt1lock.org Remove lock to reply.
Perplexed in Peoria
"Bob Kolker" <now...@nowhere.com> wrote in message news:evrn5o$fq0$1...@darwin.ediacara.org...
> Robert Karl Stonjek wrote:
>
> > Scientists shake Darwin's foundation -- chickens inherited parents' stress
> > symptoms
> >
> > Evolutionary theory ever since Darwin is based on the assumption that
> > acquired traits, such as learnt modifications of behaviour, cannot be
> > inherited by the offspring. Now, a Swedish-Norwegian research group, led by
>
Darwin didn't say it. In fact, in later editions of "Origin", he speculates
exactly the opposite.
However, the article attributes the assumption to 'evolutionary theory', rather
than to Darwin. Change the statement of the assumption to "acquired traits ...
can not be passed on for many generations" and change the time frame to
"ever since the synthesis", and now you have a statement which can almost
be defended. However, this is far from the first reported example of acquired
traits being passed on for at least a few generations. As in most of the
previous reports, the mechanism is modified (methylated) bases.
> > professor Per Jensen at Linköping university in Sweden, shows that chickens
> > can actually inherit behavioural modifications induced by stress in their
> > parents.
>
> That means stress somehow modifed the genes. Or maybe it is something
> else and the researchers have incorrectly interpreted their data.
Nope. It is just what the story says it is. A modification of the gene in
some sense, but not a modification of the sequence of bases. A fairly
complicated and error-prone process is involved in doing the post-replication
modifications, and the effect of the stress probably fades after just a few
stress-free generations. Not like a mutation, which is permanent.
Tim Tyler
You certainly do not need different DNA for
stressed parents to produce stressed offspring.
Just let the stress mess with the embryonic
developmental process a bit.
Presto: screwed up, stressed out offspring.
They will have many of the same stress-related
changes in gene expression as their parents - because
they inherit their adrenal and nervous systems from
them, and stress works in much the same way in both
of them.
Ron O
> > symptoms
>
> > Evolutionary theory ever since Darwin is based on the assumption that
> > acquired traits, such as learnt modifications of behaviour, cannot be
> > inherited by the offspring. Now, a Swedish-Norwegian research group, led by
>
It would be a neat trick because Darwin was stuck with a Lamarkian
inheritance model, that he knew was inadequate.
>
> > professor Per Jensen at Linköping university in Sweden, shows that chickens
> > can actually inherit behavioural modifications induced by stress in their
> > parents.
>
> That means stress somehow modifed the genes. Or maybe it is something
> else and the researchers have incorrectly interpreted their data.
>
> Bob Kolker
We know of epigenetic differences that can be "inherited." Just look
up imprinting where genes are silenced that are inherited from one
sex, but not the other. They can get unsilenced when inherited by the
sex that activates them.
Ron Okimoto
Douglas Clark
news:evtrr8$1ev4$1...@darwin.ediacara.org...
Wirt Atmar
> We know of epigenetic differences that can be "inherited." Just look
> up imprinting where genes are silenced that are inherited from one
> sex, but not the other. They can get unsilenced when inherited by the
> sex that activates them.
The best physical example of an epigenetic difference that is
"inherited" is the information contained in the colostrum, the first
milk that mammals suckle. The colostrum is filled with the mother's
antibodies, and in passing this material to her newborns, she passes
along the highly dialectical information about the local threat
environment she's acquired during her lifetime.
However there is a raft of cultural information that is also passed
mother to infants in a great many species. The longer the newborns
stay with their mother, the more opportunity there is for them to
acquire the knowledge the mother has learned during her lifetime, and
possibly that of her group. In humans, the acquired information that
is passed along to the children is enormous of course, everything from
language to religion to calculus.
All of these are forms of Lamarckian inheritance, but just not as
Lamarck himself imagined.
Wirt Atmar
John Wilkins
> "Bob Kolker" <now...@nowhere.com> wrote...
> > Robert Karl Stonjek wrote:
> >
> > > Scientists shake Darwin's foundation -- chickens inherited parents'=
stress
> > > symptoms
> > >
> > > Evolutionary theory ever since Darwin is based on the assumption th=
at
> > > acquired traits, such as learnt modifications of behaviour, cannot =
be
> > > inherited by the offspring. Now, a Swedish-Norwegian research group=
,
> > > led by
> >
> > Cite please. Where did Darwin say or write this?
>=20
> Darwin didn't say it. In fact, in later editions of "Origin", he specu=
lates
> exactly the opposite.
Not exactly. Darwin's "pangenesis" or "Lamarckism" is more a matter of
th einheritance of used variations and the deprecation of heredity of
unused variations. He does not suppose Lamarck's inheritance of acquired
variations.
But the ban on inheritance of acquired variations is due to Weismann,
not Darwin, and some of Darwin's followers, such as Romanes, insisted
that Weismann was going far beyond Darwin. He called these people
"neo-Darwinians" or "ultra-Darwinians"...
>=20
> However, the article attributes the assumption to 'evolutionary theory'=
,
> rather than to Darwin. Change the statement of the assumption to
> "acquired traits ... can not be passed on for many generations" and cha=
nge
> the time frame to "ever since the synthesis", and now you have a statem=
ent
> which can almost be defended. However, this is far from the first
> reported example of acquired traits being passed on for at least a few
> generations. As in most of the previous reports, the mechanism is
> modified (methylated) bases.
Epigenetic inheritance has been accepted as true for some time now,
arguably back to Waddington. So demonstration of yet another case is
hardly a "challenge" to anything but a strawman of the author's own
making.
>=20
> > > professor Per Jensen at Link=F6ping university in Sweden, shows tha=
t
> > > chickens can actually inherit behavioural modifications induced by
> > > stress in their parents.
> >
> > That means stress somehow modifed the genes. Or maybe it is something
> > else and the researchers have incorrectly interpreted their data.
>=20
> Nope. It is just what the story says it is. A modification of the gen=
e
> in some sense, but not a modification of the sequence of bases. A fair=
ly
> complicated and error-prone process is involved in doing the
> post-replication modifications, and the effect of the stress probably
> fades after just a few stress-free generations. Not like a mutation,
> which is permanent.
Eva Jablonka has gathered together the evidence in favour of methylation
and other epigenetic inheritance. Unfortunately she and her
collaborators also have employed the "Lamarckism" and "challenge to
Darwinism" gambits...
--=20
John S. Wilkins, Postdoctoral Research Fellow, Biohumanities Project
University of Queensland - Blog: scienceblogs.com/evolvingthoughts
"He used... sarcasm. He knew all the tricks, dramatic irony, metaphor,=20
bathos, puns, parody, litotes and... satire. He was vicious."
John Wilkins
No they aren't Wirt. All forms of proposed Lamarckian inheritances were
structural biological, not cultural. Immune antibody inheritance would
be seen as a single generation effect by the neo-Lamarckians and
precisely not what they were proposing.
And culture is not Lamarckian on any reasonable interpretation, Gould
and Lewontin notwithstanding, because what is passed on - the memes if
you like that sort of terminology - are not evolving by any mode other
than trial and error. The fact that they are acquired by a biological
adult is as irrelevant as the fact that an ecosystem acquires novel gene
frequencies is to the neo-Darwinian view of evolution.
--
John S. Wilkins, Postdoctoral Research Fellow, Biohumanities Project
University of Queensland - Blog: scienceblogs.com/evolvingthoughts
"He used... sarcasm. He knew all the tricks, dramatic irony, metaphor,
Anthony Cerrato
"Wirt Atmar" <at...@aics-research.com> wrote in message
news:f00bhk$4r0$1...@darwin.ediacara.org...
Thanx muchly for a nice clear and simple example of an
epigenetic factor--and I agree that such things indeed fall
under the rubric of "Lamarckian" factors (I feel Lamarck is
done a great disservice every time the word epigenetic is
used for such things which only differ from the initial
historical view of the word "Lamarckian" in the technicality
of degree.)
Your example is precise and I only wonder if it can/should
be extended to any of the myriad factors that reside in the
local spacetime region prior to, during, and immediately
after (and maybe ever after also?) birth--IOW, for ex., any
spatially and/or temporally localized environmental
chemicals, biochemicals, e.g., neurotransmitters etc., and
so on which can impinge upon, affect, modify, mediate, genes
or the timing in their activation schedule, and so forth.
Perhaps even radiation, thermal variations, and other
mutagenic factors should be considered as Lamarckian also,
huh? :)) ...tonyC (terminology bug!)
Tim Tyler
> Wirt Atmar <at...@aics-research.com> wrote:
> > All of these are forms of Lamarckian inheritance, but just not as
> > Lamarck himself imagined.
>
> No they aren't Wirt. All forms of proposed Lamarckian
> inheritances were structural biological, not cultural.
What does 'structural biological inheritance' even mean?
You are suggesting bones and muscles only - and not
intangibles like behaviour?
Lamarckian inheritance /commonly/ refers to the inheritance
of traits acquired during an organism's lifespan. IMO,
immune system responses surely qualify as such a trait.
> Immune antibody inheritance would be seen as a single
> generation effect by the neo-Lamarckians and precisely not
> what they were proposing.
>
> And culture is not Lamarckian on any reasonable
> interpretation, Gould and Lewontin notwithstanding, because
> what is passed on - the memes if you like that sort of
> terminology - are not evolving by any mode other than trial
> and error.
Surely memetic evolution mechanisms are a superset of
those available to genetic evolution so far - since
such ideas are most easily manipulated by intelligent
agents using engineering principles - and existing
mechanisms of evolution are still available if needed -
via the use of genetic algorithms.
Not only do memes evolve, they evolve /much/ better and
faster than genes ever did - as the current spike in the
development rate clearly indicates.
John Wilkins
> J. Wilkins wrote:
> > Wirt Atmar <at...@aics-research.com> wrote:
>
> > > All of these are forms of Lamarckian inheritance, but just not as
> > > Lamarck himself imagined.
> >
> > No they aren't Wirt. All forms of proposed Lamarckian
> > inheritances were structural biological, not cultural.
>
> What does 'structural biological inheritance' even mean?
Phenotypic inheritance, although the term "phenotype" is much later, and
the distinction between phenotype and genes was not even a coherent one
when Lamarck, or even the early neo-Lamarckians, wrote. We must be
careful not to import later issues into the past.
>
> You are suggesting bones and muscles only - and not
> intangibles like behaviour?
Earlier writers did speak of "habit", but they seem to me to have meant
it in the sense of "behaviour appropriate to a habitat" rather than
inherited behaviour.
>
> Lamarckian inheritance /commonly/ refers to the inheritance
> of traits acquired during an organism's lifespan. IMO,
> immune system responses surely qualify as such a trait.
The contrast between inherited and acquired traits relative to the
organism's lifespan is late - it is basically something in response to,
or acceptance of, Weismann's barrier c1895 (I can't be bothered looking
up the exact date right now). Since "Lamarckism" has a 90 year prior
history, that contrast is not necessary nor historically accurate.
As to immune responses, given that until Burnet's clonal selection
theory there was no clear conception of immunity being acquired (the
ruling view was that it was there in potentia) you are using a
misrepresentation of a 19th century view to characterise a late 20th
century theory. I think that is just asking for confusion.
And since clonal selection is about an evolutionary (i.e., selection)
process that takes place *within* the body, the relevance of the
organism as anything other than the ecological field or environment in
which it occurs is moot.
>
> > Immune antibody inheritance would be seen as a single
> > generation effect by the neo-Lamarckians and precisely not
> > what they were proposing.
> >
> > And culture is not Lamarckian on any reasonable
> > interpretation, Gould and Lewontin notwithstanding, because
> > what is passed on - the memes if you like that sort of
> > terminology - are not evolving by any mode other than trial
> > and error.
>
> Surely memetic evolution mechanisms are a superset of
> those available to genetic evolution so far - since
> such ideas are most easily manipulated by intelligent
> agents using engineering principles - and existing
> mechanisms of evolution are still available if needed -
> via the use of genetic algorithms.
>
> Not only do memes evolve, they evolve /much/ better and
> faster than genes ever did - as the current spike in the
> development rate clearly indicates.
None of which makes them "Lamarckian", since the entities involved in
that evolutionary process aren't organisms, but minds, or social
profiles, or thinkers, or traditions. And they do not "acquire traits in
maturation", but are themselves simply the outcome of selection (or
drift) in a population of reproducing entities.
The confusion here is one of categories - the entities in genetic
evolution are organisms (or antibodies in the immune case) or viruses,
etc. What sets the benchmark entity here is what is being reproduced by
way of the genes/DNA. But to talk about the evolution of one entity
(say, antibodies or cultural notions) in terms of the entities of
another evolutionary process (the organisms and their parental lineages,
or worse, species and their ancestor-descendent lineages) is to simply
make a basic error - you are not comparing like against like.
The inheritance of wealth is not Lamarckian even if it tracks genetic
lineages, because the inheritances match more or less independently, as
shown by the fact that inheritance can be nonbiological, or be subverted
by company law, etc. So if you are talking about the evolution of
wealth, be sure to track the right entities (corporations or legal
individuals, or market agents, or whatever). And when you do, you find
that at *that* level, it is a Darwinian* process.
There is a kind of level coevolution that occurs between these disparate
substrates. If one evolutionary process can go on without being tied
obligately to another, then the entities that evolve are distinct. I use
the metaphor of laminar flows in a stream - they may interact, but if
they are not directly and universally correlated to each other they are
distinct processes.
*I have real problems with that adjective, but it here means "not
something that is forward-looking".