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Author Topic: Are Tasmanian Devils experiencing Lamarckian style evolution this very moment?  (Read 10503 times)

Offline echochartruse

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Quote from: PNAS Life-history change in disease-ravaged Tasmanian devil populationsAbstract. http://www.pnas.org/content/early/2008/07/07/0711236105

Changes in life history are expected when new sources of extrinsic mortality impact on natural populations. We report a new disease, devil facial tumor disease, causing an abrupt transition from iteroparity toward single breeding in the largest extant carnivorous marsupial, the Tasmanian devil (Sarcophilus harrisii), in which males can weigh as much as 14 kg and females 9 kg. This change in life history is associated with almost complete mortality of individuals from this infectious cancer past their first year of adult life. Devils have shown their capacity to respond to this disease-induced increased adult mortality with a 16-fold increase in the proportion of individuals exhibiting precocious sexual maturity. These patterns are documented in five populations where there are data from before and after disease arrival and subsequent population impacts. To our knowledge, this is the first known case of infectious disease leading to increased early reproduction in a mammal. The persistence of both this disease and the associated life-history changes pose questions about longer-term evolutionary responses and conservation prospects for this iconic species.

The fight for survival has genetically changed the Tassie Devil to breed earlier. This stress apon the animal that is native to Tasmania, Australia is caused by the facial cancer that is contagious and travelling through the entire population. It is fatal and can kill as soon as 3 months after getting the cancer.

The Tassie Devil's genes have changed allowing them to breed earlier in hope to pass onto their young some type of immunity so it seems.

Is this Lamarckian?



 

Offline Bored chemist

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No, earlier reproductions is a Darwinian response to an external, environmental stimulus; the cancer.
Those who happened to breed younger had a better chance of doing so before being killed by cancer; their progeny inherited this trait and were also, therefore, more likely to breed.
It's notable that in humans too, we tend to breed before we get old enough to get cancer.
 

Offline echochartruse

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Then if the young inherit antibodies or immunity is this an acquired trait?
 

Offline imatfaal

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Echo

If anything is going to be able to show lamarckism (even though I doubt anything would) it is could be a strange fact set as this; HOWEVER from the paper:
Quote
At this stage, all we have evidence for is a phenotypic response.

I have not read the paper thoroughly but I could not find any mention of the genetic change that you mention.  the strange circumstances have lead the authors to say that this we may be able to observe rapid adaptation.  at no point do the authors even posit the notion that genotype passed onto progeny may be different from that of the parents.

this is definitely not proof of lamarckism - the only evidence so far is phenotypical; although a darwinian response is clearly hinted at and expected.

Then if the young inherit antibodies or immunity is this an acquired trait?
Infants can acquire antbbdies from their mother (just as we do) but this is due to shared systems and not genetic. on acquired immunity;  there is a lack of diversity in tassies, especially in the major histopathological complex and this hampers the ability to fight disease.  those individuals with a better immune response are more likely to breed than those without - this is darwinism, even if at an increased rate.

Matthew
 

Offline BenV

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I've explained this in the other threads.

The disease is driving a population structure change.  This in itself has nothing to do with DNA.

A result of the population structure change is that different individuals have breeding access (in this case, younger individuals).  As a result, one would expect to see genetic changes in the population.
 

Offline Bored chemist

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Then if the young inherit antibodies or immunity is this an acquired trait?
They don't.
 

Offline echochartruse

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It's notable that in humans too, we tend to breed before we get old enough to get cancer.

Then is the age of sexual activity related to our genes and the length of our life?

Echo

If anything is going to be able to show lamarckism (even though I doubt anything would) it is could be a strange fact set as this; HOWEVER from the paper:
Quote
At this stage, all we have evidence for is a phenotypic response.

I have not read the paper thoroughly but I could not find any mention of the genetic change that you mention.  the strange circumstances have lead the authors to say that this we may be able to observe rapid adaptation.  at no point do the authors even posit the notion that genotype passed onto progeny may be different from that of the parents.

this is definitely not proof of lamarckism - the only evidence so far is phenotypical; although a darwinian response is clearly hinted at and expected.

Then if the young inherit antibodies or immunity is this an acquired trait?
Infants can acquire antibodies from their mother (just as we do) but this is due to shared systems and not genetic. on acquired immunity;  there is a lack of diversity in tassies, especially in the major histopathological complex and this hampers the ability to fight disease.  those individuals with a better immune response are more likely to breed than those without - this is darwinism, even if at an increased rate.

Matthew


Yes there is limited phenotypic variability. It is under stress these animals are changing and Lamarckan inheritance allows quicker genetic adaptation to new environment which has happened in the Tassie Devils, as I see, with entire populations breeding earlier because of their contagious fatal disease.

Isn't the ability for the Tassie Devils to breed earlier genetic?

Isn't this both epigenetic and genetic.


At present there is no immunity for the mother/father to pass on.

Chance through random mutations in an organism's doesn't explain how rare mutations can help organisms of every size and variety adapt quickly enough through time.

Only time will tell if antibodies found in one devil that is passed on, want this show a Lamarchian inheritance? These animals have no antibodies at present, they are virtually clones.

Sorry too many questions again.
« Last Edit: 09/07/2010 02:05:25 by echochartruse »
 

Offline echochartruse

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I've explained this in the other threads.

The disease is driving a population structure change.  This in itself has nothing to do with DNA.

A result of the population structure change is that different individuals have breeding access (in this case, younger individuals).  As a result, one would expect to see genetic changes in the population.

Even though they have been described as clones?
 

Offline Bored chemist

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They are massively inbred so they don't have much genetic diversity, but they are not clones.

The story of these animals is all perfectly consistent with Darwinian evolution. You have already been told that.

Why do you keep trying to pretend that it's not?
 

Offline imatfaal

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Yes there is limited phenotypic variability. It is under stress these animals are changing and Lamarckan inheritance allows quicker genetic adaptation to new environment which has happened in the Tassie Devils, as I see, with entire populations breeding earlier because of their contagious fatal disease.
The paper clearly states that only changed that is evinced is phenotypic. The paper, which is available in full on line, explains simply the mechanisms that allow earlier than normal breeding; Larmarckism is NOT one of these - in fact genetic change of any sort is not posited as an explanation.

Quote
Isn't the ability for the Tassie Devils to breed earlier genetic?
Isn't this both epigenetic and genetic.
No it isnt.  The Devils have always had this ability but other pressures have meant that their breeding patterns were different.  Please read the full paper - the bulk of the paper is about phenotype variation and precocial breeding.


Quote
Chance through random mutations in an organism's doesn't explain how rare mutations can help organisms of every size and variety adapt quickly enough through time.
 
It does explain it beautifully.  The species who have random variations that help them breed in a particular environment survive; there are a multitude of variations that have lead no-where and as they provided no breeding advantage make either no difference or sometime make a negative impact.  when an isolated species is under sever pressure latent genetic difference might come to the fore and suddenly become important.  those devils that had phenotype that allowed early breeding (and might have been neutral or slightly disadvantaged under previous environmental constraints) suddenly have a massive advantage; they might be much more likely to breed.  and their progeny will also have that propensity to breed earlier.  This is darwinian.

Quote
Only time will tell if antibodies found in one devil that is passed on, want this show a Lamarchian inheritance? These animals have no antibodies at present, they are virtually clones.
not sure what you mean by this

could you explain a mechanism (even if a bit hand-wavy) of how a mother that contracts a form of cancer can pass a different and advantageous genotype to her progeny.  this is necessary to accept lamarckism. 

please go back and read the actual paper - it is here http://www.pnas.org/content/early/2008/07/07/0711236105.full.pdf+html  its clear and nicely written and really does not support your claims

matthew
 

Offline echochartruse

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it was a question not a claim
 

Offline echochartruse

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Quote from: http://www.pnas.org/content/early/2008/07/07/0711236105.full.pdf+html
At this stage, all we have evidence for is a
phenotypic response. We suggest that DFTD is a novel, strong
selective agent for life-history change that might lead to rapid
adaptation toward a population genetically and demographically
more robust to the effects of DFTD.
To our knowledge, this is the first known case of infectious
disease leading to increased early reproduction in a mammal.

phenotype definition = The detectable characteristics associated with a particular genotype and its environment.

Yes these animals are responding to their environment and are under stress.

Is the ability for an animal to sexually mature early based on their genes?
All reference I've found to sexual maturity mentions genes/genetics.
I understand this is brought about by phenotypic plasticity, [the ability for an animal to rapidly adapt to it's environment]

Quote from:  http://www.pnas.org/content/early/2008/07/07/0711236105.full.pdf+html
We suggest that DFTD is a novel, strong
selective agent for life-history change that might lead to rapid
adaptation toward a population genetically and demographically
more robust to the effects of DFTD.

Wasn't Lamarckian's idea that evolution occurred and proceeds in accordance with natural laws and could be acquired and inherited?
 

Offline Bored chemist

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Why can't you get to grips with the idea that this isn't a case of Lamarkian evolution?
 

Offline imatfaal

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Your two quotes explain why this is not Lamarckism. 

The first quote deals with a reaction based on phenotype - ie this is genetic-change neutral.  genetically identical animals react differently in different environments.  This CANNOT be lamarckism as there is no genetic change. 

The second quote shows that the researchers expect, in time, that darwinian evolution will occur more rapidly than usual.  this is adaptation through natural selection; those animals with a 'useful' genotype breed more.

strong larmarckism states that an individual animal can alter its genotype in response to an environmental factor; this is generally accepted as untrue and impossible.  in a truer sense of the idea that was originally propounded it is claimed that over generations the gene pool of a species will adapt to environmental pressures without natural selection of beneficial genes through differential rates of breeding.  neither of these have ever been proved or any real evidence put forward in their favour other than anecdote.

the fact that it is difficult to comprehend how the complexity of nature can arise without a guiding hand or designer is one reason that darwin is so celebrated, the idea is ground breaking, counter-intuitive and yet able to withstand all challenges so far.  evolutionary timescales are normally so vast that the short-lived human might have trouble understanding the concept - the unusual situation in tasmania means that we will be able to observe (still over many many years) the first stages of adaptation of a mammal in the wild.  it is difficult not to be amazed by evolution through natural selection if you have properly understood it - but there is nothing in the complexity of life that is not explained by it.  there is no need to search for a design or the hand of a creator. 

any alternative theory must advance by showing a fact set that cannot be explained by darwinian evolution and can be explained by the new alternative; the predictions made by any new theory can then be tested.  darwinian evolution is the subject of rigorous and regular challenge and has not be found to be flawed yet, despite the huge effort and resources placed in the hands of ideologically motivated opponents.

matthew

 

Offline echochartruse

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OK, it is not Lamarckism.

Again, Isn't maturing earlier to breed genetic?


Your two quotes explain why this is not Lamarckism. 

The first quote deals with a reaction based on phenotype - ie this is genetic-change neutral.  genetically identical animals react differently in different environments.  This CANNOT be lamarckism as there is no genetic change. 

The second quote shows that the researchers expect, in time, that darwinian evolution will occur more rapidly than usual.  this is adaptation through natural selection; those animals with a 'useful' genotype breed more.




Quote
strong larmarckism states that an individual animal can alter its genotype in response to an environmental factor; this is generally accepted as untrue and impossible.


Tibetan Adaptation to High Altitude Occurred in Less Than 3,000 Years. http://www.sciencedaily.com/releases/2010/07/100701145519.htm

is this Lamarckism?

Quote
  in a truer sense of the idea that was originally propounded it is claimed that over generations the gene pool of a species will adapt to environmental pressures without natural selection of beneficial genes through differential rates of breeding.  neither of these have ever been proved or any real evidence put forward in their favour other than anecdote.

the fact that it is difficult to comprehend how the complexity of nature can arise without a guiding hand or designer is one reason that darwin is so celebrated, the idea is ground breaking, counter-intuitive and yet able to withstand all challenges so far.  evolutionary timescales are normally so vast that the short-lived human might have trouble understanding the concept - the unusual situation in tasmania means that we will be able to observe (still over many many years) the first stages of adaptation of a mammal in the wild.  it is difficult not to be amazed by evolution through natural selection if you have properly understood it - but there is nothing in the complexity of life that is not explained by it.
 there is no need to search for a design or the hand of a creator.


Who's searching, you mentioned 'the hand of a creator" not I.

Quote
any alternative theory must advance by showing a fact set that cannot be explained by darwinian evolution and can be explained by the new alternative; the predictions made by any new theory can then be tested.  darwinian evolution is the subject of rigorous and regular challenge and has not be found to be flawed yet, despite the huge effort and resources placed in the hands of ideologically motivated opponents.

matthew


 

Offline echochartruse

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Sorry I am having difficulty in understanding........

The meaning of Phenotype

Quote from: http://www.thefreedictionary.com/phenotype
phe·no·type  (fn-tp)
n.
1.
a. The observable physical or biochemical characteristics of an organism, as determined by both genetic makeup and environmental influences.
b. The expression of a specific trait, such as stature or blood type, based on genetic and environmental influences.
2. An individual or group of organisms exhibiting a particular phenotype.

Yes it is expected that the Devils will breed earlier as they are doing now and their offspring will inherit immunity.

Sorry again for not grasping Lamarckism, I've read some reports and I must be misinterpreting.
Is there somewhere I can read about Lamarckism that is simple to understand?

this is interesting
Quote from: http://www.sciencedaily.com/releases/2007/08/070818112338.htm
Bacteria Mutate Much More Than Previously Thought
« Last Edit: 13/07/2010 09:45:18 by echochartruse »
 

Offline imatfaal

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OK, it is not Lamarckism.
Again, Isn't maturing earlier to breed genetic?
No; the only evidence gathered in that paper was that it was not a genetic change.  environmental and demographic pressures beforet he disease started affecting the population meant that the animals matured at a slower rate and bred less precociously.  the changed pressures after the onset meant that they matured more quickly.  the phenotype is the expression of the genotype under environmental conditions: the environment changed and the SAME genotype was expressed differently to result in a phenotype that matured more quickly.  Simplistically, we could guess that prior the disease if a young male tried to breed he would be severely mauled by a bigger older adult (he should save his energy for growth and fight to breed next year); but with the disease that same young male has no older bigger adult males to maul him if he tries to breed (they died), so he does breed.  As this is an example with just one animal surely you agree that this is not genetic.  It is possible that this situation might change as I have discussed in previous post.

You may not have mentioned a creator - but in a huge number of posts on various threads you ignore accepted and well-founded science to clutch at the possibility that genetic change does not proceed through darwinian natural selection.  You seem to be searching for something - and it is something that I cannot see any physical or scientific evidence in favour of, or need for; thus I presumed a search for a supernatural component.

If you have no desire to insert supernatural factors - would you answer my previous question?
Quote
could you explain a mechanism (even if a bit hand-wavy) of how a mother that contracts a form of cancer can pass a different and advantageous genotype to her progeny.  this is necessary to accept lamarckism.


With great respect, before reading up on Lamarck -  please look in more depth at the mainstream ideas; the amazing conceptual leaps in theory of the 19th century (the voyage of the beagle etc), the groundbreaking discoveries in the mechanisms of inheritance of the 20th century, and the continued exploration and validation of these concepts that continues to this day.  Whilst science must never be wedded to orthodoxy; it is essential that well-proven theories are challenged from a position of knowledge rather than supposition.

Matthew
 

Offline echochartruse

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OK but non competition in captivity does not result in breeding earlier. The zoos here have very good facilities and food is plentiful. Limited and controlled numbers of male to females, but never has it been recorded that they matured earlier to breed. This is documented as a result of their disease.

I am not searching for supernatural explaination. Best not to assume.
Quote
strong larmarckism states that an individual animal can alter its genotype in response to an environmental factor
Is this the mechanism you ask for to be explained?
Mothers who have breast cancer can pass on the gene to their children, yet not every female following will get breast cancer even though they have the genes for this disease. It is environment/lifestyle regulated. In 2007 science has found that ST14, microRNA, inhibits both cell growth and cell invasion, suggesting that ST14 is a breast cancer tumor suppressor gene, which is also inheritable.

Quote from:  http://www.sciencedaily.com/releases/2009/09/090915100955.htm
Genes May Explain Why Children Who Live Without Dads Have Earlier Sex
Mendle and her colleagues looked at more than 1,000 cousins ages 14 and older from the National Longitudinal Survey of Youth. The study design tested for genetic influences as well as factors such as poverty, educational opportunities, and religion. It compared children who were related in different ways to each other, and who differed in whether they'd lived with their fathers. The more genes the children shared, the more similar their ages of first intercourse—regardless of whether or not the children personally had an absent father. This finding, the researchers say, suggests that environmental theories don't fully explain the puzzle. Instead, genetic influence can help us understand the tie between fathers' absence and early sex.

Contrary to your ideas I believe that the Devil's ability to mature early is not a decision made by them by choice but rather governed by genetics.

Quote
Cornell Sheep Program researchers have discovered an unusual form of a gene that prompts ewes to breed out of season as well as conceive at younger ages and more frequently.
http://www.sciencedaily.com/releases/2009/08/090806112401.htm
 

Offline Bored chemist

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"Is this the mechanism you ask for to be explained?
Mothers who have breast cancer can pass on the gene to their children, yet not every female following will get breast cancer even though they have the genes for this disease. It is environment/lifestyle regulated. In 2007 science has found that ST14, microRNA, inhibits both cell growth and cell invasion, suggesting that ST14 is a breast cancer tumor suppressor gene, which is also inheritable. "
No, because it's nothing to do with passing on an acquired trait.
Even if you are right about this
"I believe that the Devil's ability to mature early is not a decision made by them by choice but rather governed by genetics."
then it's still Darwinian.
Those who happened to be genetically inclined to breed earlier did so. They had more offspring before they got killed by cancer. As a result, their progeny did better than those animals who didn't breed early.
No need for Lamarckianism.



 

Offline imatfaal

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OK but non competition in captivity does not result in breeding earlier. The zoos here have very good facilities and food is plentiful. Limited and controlled numbers of male to females, but never has it been recorded that they matured earlier to breed. This is documented as a result of their disease.
Captive breeding programmes introduce whole new environmental pressures

Quote
strong larmarckism states that an individual animal can alter its genotype in response to an environmental factor
Is this the mechanism you ask for to be explained?

No. BC covered why not.

Quote
Contrary to your ideas I believe that the Devil's ability to mature early is not a decision made by them by choice but rather governed by genetics. 

These are not my ideas!  Evolution through natural selection is basic science.  To challenge this you need to provide a mechanism, even very basic one, of how this might happen.  Without need to rehearse details and bio-chemical pathways, and in the most hand-wavy way; how does a mother pass on a genetic inheritance to her off-spring that has been changed to meet environmental pressures and is not solely determined by her parents' dna?

Matthew
 

Offline echochartruse

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Contrary to your ideas I believe that the Devil's ability to mature early is not a decision made by them by choice but rather governed by genetics. 

These are not my ideas!  Evolution through natural selection is basic science.  To challenge this you need to provide a mechanism, even very basic one, of how this might happen.  Without need to rehearse details and bio-chemical pathways, and in the most hand-wavy way; how does a mother pass on a genetic inheritance to her off-spring that has been changed to meet environmental pressures and is not solely determined by her parents' dna?

Matthew



I find it weird that both Lamarck and Darwin never knew about DNA,neither did anyone else until quiet recently yetwe must prove DNA is not involved in phisycal change to accept or dismiss either theory.

phenotype is determined by both genetic and environmental influences.

The devil's situation is discribed as phenotype.

Some here disagree and say there is no evidence for genetic change in order for them to mature early to breed. Even though I have found scientific studies relating to sheep where a specific gene has been identified that is responsible for out of season, early breeding see above link.

Yes, I accept 'Natural Selection'!.. Those that survive, survive. Those that don't, don't. It's so basic.

To answer your question
Quote
how does a mother pass on a genetic inheritance to her off-spring that has been changed to meet environmental pressures and is not solely determined by her parents' dna?

Like the Tibeans who have a specific gene turned on so they can cope with the altitude they live at.
At one point in time, prior to our knowledge of DNA, one or possibly more Tibetans geneome changed, shuffling genes to meet their environmental pressures and since then this aquired trait has been inherited throughout the population who live there.

The Devils in Tasmania before 1996 had no genetic diversity, science describing them as 'clone like'. Now the Eastern population of Tasmanian Devils are now genetically different from the western population of Tasmanian Devils.

A taste (like or dislike) for a specific food can be aquired and geneticaly inherited. Therefore, inheritance may be entirely about genes. Lamarch and Darwin, not knowing about DNA would never have asked themselves this question.

BUT as we see from any evolution it only takes one to aquire the change in the genome for others to inherit this change depending on environment, lifestyle of course.

So I hope you see I'm not trying to prove, it is done by magic or a creator or whatever as you assume. What I am saying is that traits are aquired and inherited.
« Last Edit: 18/07/2010 02:22:06 by echochartruse »
 

Offline imatfaal

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I find it weird that both Lamarck and Darwin never knew about DNA,neither did anyone else until quiet recently yetwe must prove DNA is not involved in phisycal change to accept or dismiss either theory.
Now that we can directly probe the DNA it is easier - but it is by no means essential.  The difference between darwinian and lamarckian evolution can be seen by tracing family trees and speeds/varieties of adaptation.

Quote
phenotype is determined by both genetic and environmental influences.
The devil's situation is discribed as phenotype.
  the phenotype is the manifestation of the genetic blue print under certain environmental circumstances - the change in this case is a change in how the body and physical form has adapted to change in situation without a genetic change.

Quote
Yes, I accept 'Natural Selection'!.. Those that survive, survive. Those that don't, don't. It's so basic.
  Yes; but it's breed not survive

To answer your question
Quote
how does a mother pass on a genetic inheritance to her off-spring that has been changed to meet environmental pressures and is not solely determined by her parents' dna?

Quote
Like the Tibeans who have a specific gene turned on so they can cope with the altitude they live at.
At one point in time, prior to our knowledge of DNA, one or possibly more Tibetans geneome changed, shuffling genes to meet their environmental pressures and since then this aquired trait has been inherited throughout the population who live there.

A single pre-existing gene (in a portion of population) that is turned on when environmental circumstances change (this is a phenotype change) and thus becomes a positive selective factor over generations (this is a standard evolution) does not support larmarckism.

Quote
A taste (like or dislike) for a specific food can be aquired and geneticaly inherited. 
You need to be more exact - changes in the gene are not caused by environmental factors and then passed on.  they orginate in the gene and through environmental pressures some are selected for and others are not

Quote
Therefore, inheritance may be entirely about genes.
It is entirely about genes.  if you disagree - what else is passed on to progeny?

Quote
Lamarch and Darwin, not knowing about DNA would never have asked themselves this question.
  Darwin thought in terms of the gemulle, even Abbe Mendel thought in terms of a unit of inheritance. We do not need the bio-chemical knowledge of DNA structure to understand genetic inheritance. 

Quote
BUT as we see from any evolution it only takes one to aquire the change in the genome for others to inherit this change depending on environment, lifestyle of course. What I am saying is that traits are aquired and inherited. 
Yes and no. Traits are not acquired and inherited per se - a genetic change occurs (perhaps in distant past) and environmental conditions create situation that allows positive breeding differentiation. 

There is no correlation between the actual initial genetic change and the particular environmental circumstances of the individual animal.

Matthew   
 

Offline echochartruse

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Phenotype is the physical manifestation of a genetic trait, resulting from a specific genotype  and its interaction with the environment.
http://www.cdphe.state.co.us/ps/genetics/glossary.html

'Manifestation of a genetic trait', yet you say it is not genetic - who is right who is wrong - is there 2 different definitions?

It has ben proven that breeding early is a genetic change.


Natural selection - those that survive, survive and breed, those that done't survive don't survive and therfore don't breed.

Truely I am just trying to understand without bias.

Lamarckian  inheritance, as I understand, is, environmentally directed epigenetic changes.
 
epigenetics is where specific genes are turned on or off and inherited, such as the Tibetans.
Mutations to genes cause disease. These mutations can be inherited.

Phenotype changes are both environmental and genetic!? is that right?

I'm having trouble here as you say phenotype is not genetic so that makes me think it's epigenetic.

Can someone give me an honest description of the differences between epigenetic and phenotype?

From what I understand phenotype is directed by epigenetics.....??
 

Offline imatfaal

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Echo -  I have really tried to explain where you are going wrong but it seems that I don't have the skills to properly demonstrate where you are going astray. I am afraid that you need to read up on basic genetics, you are running before you can walk. 

Epigenetics, larmarckism, non-random genetic change etc are fringe topics (some exciting, others a bit para-science) that can only be properly understood and probed from a position of knowledge of the proven and well researched science.  I realise you are seeking greater understanding and insight but you must start from a more basic level.  there are excellent entry level books on evolution - and wikipedia has a superb section with multiple pages. 

its a marvellous topic and one of the wonders of science; it is ever changing and advancing; and research is coming from every conceivable disciplinary angle - but a firm foundation is needed to build new ideas.  Sorry I cannot help you more but I just don't have the didactic skills to get through to you how you are misunderstanding the fundamentals of the topic. 
With best regards

Matthew
 

Offline Bored chemist

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Imatfaal, I'm not sure it's a lack of teaching skills on your part that's the problem here.

Echo,
This is how wiki describes Lamarck's ideas.

"Lamarck has been credited in some textbooks and popular culture with developing two laws:
In every animal which has not passed the limit of its development, a more frequent and continuous use of any organ gradually strengthens, develops and enlarges that organ, and gives it a power proportional to the length of time it has been so used; while the permanent disuse of any organ imperceptibly weakens and deteriorates it, and progressively diminishes its functional capacity, until it finally disappears.
All the acquisitions or losses wrought by nature on individuals, through the influence of the environment in which their race has long been placed, and hence through the influence of the predominant use or permanent disuse of any organ; all these are preserved by reproduction to the new individuals which arise, provided that the acquired modifications are common to both sexes, or at least to the individuals which produce the young."

As far as I can see he doesn't mention epigentics, not could he because nobody had any idea how genetics worked at that time.

The devils are breeding earlier than their forebears did.
There are two plausible reasons for this
It's genetic; those devils which happened to have a genetic predisposition to breed young have enjoyed greater success because they bear young before the cancer gets them. (I accept that the genetic evidence seems to indicate this isn't the reason- but I'm including it for completeness).
The other possibility is that it's behavioural; normal behaviour is that the oldest animals in the group breed while the younger ones don't. The cancer kills the older animals and the younger ones left behind are therefore the oldest. The oldest animals are still the ones that breed, but they are younger than they used to be.

Neither of these has anything to do with the concept that "a more frequent and continuous use of any organ gradually strengthens, develops and enlarges that organ, and gives it a power proportional to the length of time it has been so used;"
or that "All the acquisitions or losses wrought by nature on individuals, through the influence of the environment in which their race has long been placed, and hence through the influence of the predominant use or permanent disuse of any organ; all these are preserved by reproduction" so it has absolutely nothing to do with Lamarckian evolution.
There is no acquired trait that is inherited. The traits of either adventitious earlier breeding or only the oldest in the group breeding were there before the cancer. Epigenetics doesn't alter this.
 

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