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Author Topic: How big a role does the epigenome play in evolution?  (Read 56296 times)

Offline echochartruse

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Re: How big a role does the epigenome play in evolution?
« Reply #75 on: 13/04/2010 04:38:30 »
Epigenetic regulation may be an important mechanism of both preserving and modifying genomic structure.

Quote from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2691666/

Both genetic and epigenetic changes contribute to development of human cancer.
... While there has been considerable progress in understanding the impact of genetic and epigenetic mechanisms in tumourigenesis, there has been little consideration of the importance of the interplay between these two processes.

A transposon-induced epigenetic change leads to sex determination in melon
Quote from: http://www.nature.com/nature/journal/v461/n7267/full/nature08498.html
Sex determination in plants leads to the development of unisexual flowers from an originally bisexual floral meristem1, 2. This mechanism results in the enhancement of outcrossing and promotes genetic variability, the consequences of which are advantageous to the evolution of a species3.

The behavior of a person's genes doesn't just depend on the genes' DNA sequence--it's also affected by so-called epigenetic factors.

http://www.nature.com/scitable/topicpage/Epigenetic-Influences-and-Disease-895
http://www.nature.com/scitable/topicpage/Gene-Expression-Regulates-Cell-Differentiation-931

Quote
........In addition, gene expression changes can lead to changes in an entire organism.

......DNA and its associated histone  proteins (together known as chromatin) can be chemically modified by a cell's own machinery.

....Together, these lines of evidence have led to an emerging hypothesis that cell-cell signaling and epigenetic changes converge to guide cell differentiation  decisions both during development  and beyond.

I would say that epigentics doesn't need to modify DNA to cause these changes and definitely has an influence in evolution.


« Last Edit: 13/04/2010 04:50:37 by echochartruse »
 

Offline echochartruse

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Re: How big a role does the epigenome play in evolution?
« Reply #76 on: 13/04/2010 04:48:08 »
Quote from: http://www.abc.net.au/science/articles/2009/11/26/2754494.htm?topic=
Scientists create Chinese 'gene map'
A large genetic analysis of ethnic Chinese has revealed subtle genetic differences within the world's most populous nation.........
"Different dialect groups are definitely not identical ... language is a reflection of our evolution, that's why you see the differences," says Liu.

This is an example of genetic and epigentics working together to create subtle genetic differences
 

Offline Geezer

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Re: How big a role does the epigenome play in evolution?
« Reply #77 on: 13/04/2010 07:14:31 »

I would say that epigentics doesn't need to modify DNA to cause these changes and definitely has an influence in evolution.


You don't say! (Well, I suppose you did.)

Er, but how exactly do parents pass on their inherited characteristics by means other than the transmission of their DNA?
 

Offline echochartruse

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Re: How big a role does the epigenome play in evolution?
« Reply #78 on: 13/04/2010 19:05:38 »
"Selective Pressure"

Quote from:  http://blogs.monografias.com/sistema-limbico-neurociencias/2010/03/02/culture-and-evolution-genetic-epigenetics-exaptations-spandrels-and-jumping-genes%E2%80%A6/
The best evidence available to Dr. Boyd and Dr. Richerson for culture being a selective force was the lactose tolerance found in many northern Europeans. Most people switch off the gene that digests the lactose in milk shortly after they are weaned, but in northern Europeans — the descendants of an ancient cattle-rearing culture that emerged in the region some 6,000 years ago — the gene is kept switched on in adulthood.

Lactose tolerance is now well recognized as a case in which a cultural practice — drinking raw milk — has caused an evolutionary change in the human genome. Presumably the extra nutrition was of such great advantage that adults able to digest milk left more surviving offspring, and the genetic change swept through the population.

This instance of gene-culture interaction turns out to be far from unique. In the last few years, biologists have been able to scan the whole human genome for the signatures of genes undergoing selection. Such a signature is formed when one version of a gene becomes more common than other versions because its owners are leaving more surviving offspring. From the evidence of the scans, up to 10 percent of the genome — some 2,000 genes — shows signs of being under selective pressure.

DNA carries information. Epigenetics is the conductor/regulator/, the switch that turns genes on and off.
The information in all living things is very much the same throughout species as I have been told by TNS and is what evolution is based on as far as I can understand.

This information carried by a species can be unchanged but regulated, switched on or off.
If this information regulator had a permanent effect there would not be evolution only permanent change.
(if the sea creature left the ocean to walk on land, the information required to be able to return to water and survive would have been lost)

DNA in identical twins have exact same DNA but may have very different immunity issues.


« Last Edit: 13/04/2010 19:10:54 by echochartruse »
 

Offline norcalclimber

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Re: How big a role does the epigenome play in evolution?
« Reply #79 on: 13/04/2010 19:09:36 »
I just came across this, and I'm not sure if I am understanding or interpreting it correctly:

http://www.ncbi.nlm.nih.gov/pubmed/10690404?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_SingleItemSupl.Pubmed_Discovery_RA&linkpos=3&log$=relatedreviews&logdbfrom=pubmed

Quote
A decade of research on adaptive mutation has revealed a plethora of mutagenic mechanisms that may be important in evolution. The DNA synthesis associated with recombination could be an important source of spontaneous mutation in cells that are not proliferating. The movement of insertion elements can be responsive to environmental conditions. Insertion elements not only activate and inactivate genes, they also provide sequence homology that allows large-scale genomic rearrangements. Some conjugative plasmids can recombine with their host's chromosome, and may acquire chromosomal genes that could then spread through the population and even to other species. Finally, a subpopulation of transient hypermutators could be a source of multiple variant alleles, providing a mechanism for rapid evolution under adverse conditions.

The first part of the underlined section seems to be referring to epigenomic markers.  "Insertion elements not only activate and inactivate genes, they also provide sequence homology that allows large-scale genomic rearrangements." seems to be saying epigenomic markers are responsible for the mechanism which allows an organism to make a large mutation?

"Some conjugative plasmids can recombine with their host's chromosome, and may acquire chromosomal genes that could then spread through the population and even to other species."  This seems to be saying that certain plasmids may be able to "carry" beneficial mutations throughout a population?  If this occurs, mustn't it have evolved at some point?  The only reason I can think of as to why a mutation like that would be beneficial is because it allows beneficial mutations to be transmitted without direct mating.  If that is true, it seems to be just another element which is starting to show us just how advanced life is, and how much it seems to recognize(consciously or not) the need to evolve into a fitter organism is paramount to survival of future generations.

To be honest, I'm not precisely sure what transient hypermutators are specifically, but I'm guessing from the name that they are theoretical cellular "machines" capable of increasing the rate of mutation under adverse conditions.  I'm also guessing that the reason they are theorizing the mutators might exist is because we consistently see in experiment after experiment that beneficial mutations tend to happen very rapidly when they are really needed, but almost not at all when the organism is not under stress.  Even if the mutations afterward were indeed random, doesn't this still represent the ability of an organism to control mutation, and evolution to some extent?

If I have misunderstood anything I apologize, it is surely not my wish to put forth a misinterpretation of science.

I know the other links I posted don't specifically attribute results to epigenetics, but doesn't this one specifically state that it is epigenomic markers which "allow" large genomic changes to happen?
 

Offline echochartruse

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Re: How big a role does the epigenome play in evolution?
« Reply #80 on: 13/04/2010 19:21:46 »
L=E3

Life=epigenetics, ecology, and evolution (L=E3)
quote from Greengard, who won the 2000 Nobel Prize in Physiology or Medicine for research into how neurons communicate.
 

Offline echochartruse

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Re: How big a role does the epigenome play in evolution?
« Reply #81 on: 13/04/2010 19:35:30 »
Er, but how exactly do parents pass on their inherited characteristics by means other than the transmission of their DNA?

Please read this you may have a better understanding.
Quote from: http://pn.psychiatryonline.org/content/45/5/12.1.full
In other words, epigenetics is the place where nature and nurture converge. The genes we are born with can determine some but not all of who we are and who we become.
 

Offline norcalclimber

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Re: How big a role does the epigenome play in evolution?
« Reply #82 on: 13/04/2010 20:47:06 »
Here is a few more examples which I feel indicate epigenetics causing mutation:

http://www.gate.net/~rwms/EvoMutations.html

. . .

Sorry it took me so long, but after reading through all of those sources and watching the last 5 minutes of the Naked Science video, I still have to disagree that there's evidence for epigenetic changes causing genetic mutation.  Those experiments all show that you can "rapidly" develop a lot of genetic diversity, but they don't attribute that to epigenetics.  I still haven't seen any direct evidence of epigenetic change causing genetic mutation. There's also the difference in time scales of "rapidly."  The sources you cite seem to be talking about time scales that are long compared to the life cycle of an individual, 10,000 generations in one study and mutation probability of ~10-8 per cell division in the other.  Epigenetics seems to be a much faster process, allowing single organisms to change (so changes on the scale of 1 generation).  If epigenetics induced mutation, then I would expect it to happen orders of magnitude faster than any of those studies show. 

Again, it's not that I think epigenetics isn't interesting and promising.  It's just that there doesn't seem to be enough evidence to link it to actual genetic mutations.  If that link is made, then it certainly would change things.

The last 5 minutes of the Naked Science video "Was Darwin Wrong?" specifically states that it appears evolution can happen for faster than previously thought using epigenetic means.  The narrator actually states that new evidence shows life may be able to(and I quote) "make" evolution happen.  It also states that the answer to how whales "lost their legs" may have been initiated due to epigenetics and the expression of the PITX1 gene(I think that was the one at least).  So I'm not really sure how you could say their was no evidence for epigenetic induced mutation in the evidence I provided.

The link I posted regarding mutation of the Trp genes in e. coli bacteria states that beneficial mutations were observed at a rate which was orders of magnitude higher than what could be expected via random mutation alone.  This is exactly what is predicted if genetic evolution via epigenetically induced methods is a reality.

I didn't see how the Tasmanian devil bit applied in what echo posted, but since that post echo has posted several links which seem to me to provide legitimate evidence of epigenetically driven evolution.

I'm not sure how you can still assert that there is absolutely no evidence of epigenetically driven genetic mutation, I could understand if you had simply said that you don't feel there is enough evidence(although I disagree obviously), but to simply say there is no evidence at all?

If you are merely stating that it hasn't been proven yet, then I would have to ask how you feel about the standard model of physics?  It hasn't been proven, it has made predictions which have occurred and therefore has gained merit, but it still isn't proven.

Evolution driven by epigenomic markers certainly hasn't been proven, nor does it have as many years or predictions as the standard model has behind its belt; but it does make predictions, and those predictions have been proven.

Evolution by purely random mutation predicts a steady rate of evolution over a large time scale.  When we look at the fossil record we see this to be false, as very little evolution at all seems to have happened over the first few billion years; then a massive explosion of life seems to have occurred and continued since.  We also see repeatedly in experiments that very few beneficial mutations seem to happen when the environment isn't stressed; yet when an environment is stressed and there is even the slightest chance at all for an organism to survive, all of a sudden the necessary mutation occurs in relatively short periods of time.

The fact that our fossil record, and the last 100 years of experiments continue to have results which are predicted by epigenetic induced genetic mutation and not predicted by purely random mutation gives a great deal of weight to the theory, whether it has been "proven" yet or not. 

When you talk about the different time scales in the experiments, it is important to consider how advanced the organism in question is.  It stands to reason that if epigenetically controlled genetic mutation first evolved ~750 million years ago, then even that control should have been evolving since.  Wouldn't this result in more advanced forms of life having more advanced forms of epigenetic control?  So when we look at experiments using "simple" bacteria, their control should be "simple" as well?  Shouldn't we expect epigenetic mutations and epigenetically controlled mutations to actually take fewer generations in more complicated/advanced forms of life?

 

Offline Geezer

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Re: How big a role does the epigenome play in evolution?
« Reply #83 on: 13/04/2010 22:14:05 »
Thanks for the links Echo and Norcal (I hope you don't mind my abbreviations.)

I don't think there is any doubt that there are a great many factors involved in the development of living organisms. Genes provide a sort of underlying fabric, but there are many other factors at play. For example, just because my genes indicate that I am predisposed to develop a certain disease, it does to mean that I ever will develop that disease. It just means that I have a higher probability of developing that disease.

Let me take a shot at stating the question we are (perhaps) trying to answer.

"Can factors that affect my life directly alter the genes that I pass on to my progeny, or are the genes that I pass on to my progeny simply determined by the genes that I inherited from my parents, plus or minus some random transcription errors?"

That's probably a bit of an oversimplification of course, because I know that I really could mess up the genes that I pass on if I was exposed to a lot of radiation for example, but the effect would still be random rather than directed.

Anyway, is that an approximation for the question?
 

Offline echochartruse

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Re: How big a role does the epigenome play in evolution?
« Reply #84 on: 14/04/2010 00:00:24 »
"Can factors that affect my life directly alter the genes that I pass on to my progeny, or are the genes that I pass on to my progeny simply determined by the genes that I inherited from my parents, plus or minus some random transcription errors?"

"Transcription errors?"

Is this what is described as Random Mutation?

My personal view is that there is some type of Intelligents behind the mutations which are not errors at any length.

Quote from: http://www.abc.net.au/science/articles/2007/12/11/2115575.htm
Many of the recent genetic changes reflect differences in the human diet brought on by agriculture, as well as resistance to epidemic diseases that became mass killers following the growth of human civilisations, the researchers say.

For example, Africans have new genes providing resistance to malaria. In Europeans, there is a gene that makes them better able to digest milk as adults. In Asians, there is a gene that makes ear wax more dry.

prior to the TDFT “The majority of devils in Tasmania were immunological clones and therefore susceptible to DFTD,” Geneticist and devil researcher Dr Kathy Belov http://www.tassiedevil.com.au/research.html#different

although there was no subdivision apparent among pre-disease populations (theta=0.005, 95% confidence interval (CI) -0.003 to 0.017), we found significant genetic differentiation among populations post-disease (theta=0.020, 0.010-0.027),

Prior to the cancer appearing, the Devil’s genetic diversity was so low, it was thought that in 10 years we could lose the species.

Quote from: http://www.time.com/time/health/article/0,8599,1951968,00.html
Yes we can influence our children’s genes and our children’s children and theirs so they become alcoholics, diabetic, have cancer, schizophrenia, autism, Alzheimer's and many others. All depending on how we live our lives today.

Why Your DNA Isn't Your Destiny
By John Cloud
http://www.time.com/time/health/article/0,8599,1951968-2,00.html#ixzz0jukwTf7h

I know this is exactly what I submitted in this forum previously, hope this is easier to understand.
« Last Edit: 14/04/2010 00:01:59 by echochartruse »
 

Offline Geezer

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Re: How big a role does the epigenome play in evolution?
« Reply #85 on: 14/04/2010 00:42:57 »
"Can factors that affect my life directly alter the genes that I pass on to my progeny, or are the genes that I pass on to my progeny simply determined by the genes that I inherited from my parents, plus or minus some random transcription errors?"

"Transcription errors?"

Is this what is described as Random Mutation?

I believe that is correct. The genetic duplication process is not perfect, so in the process of copying DNA, some errors creep in. There are also external factors like, for example, radiation.

Anyway, perhaps you could answer my question. I don't think it was terribly complicated.
 

Offline Geezer

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Re: How big a role does the epigenome play in evolution?
« Reply #86 on: 14/04/2010 01:13:25 »

My personal view is that there is some type of Intelligents behind the mutations which are not errors at any length.


Of course you are entitled to hold a personal view, but if you can't prove that mutations are driven by some intelligence, then it's just your personal view. On the other hand, there is plenty of evidence that mutations are simply caused by transcription errors.

Perhaps you should start by proving that the DNA transcription process is infallible and base your argument on that.
 

Offline echochartruse

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Re: How big a role does the epigenome play in evolution?
« Reply #87 on: 14/04/2010 01:14:02 »
I believe that is correct. The genetic duplication process is not perfect, so in the process of copying DNA, some errors creep in. There are also external factors like, for example, radiation.

Anyway, perhaps you could answer my question. I don't think it was terribly complicated.

Firstly isn't radiation an environmental/epigentic issue?

If evolution only required a copy of hereditary DNA, wouldn't we be clones?

Quote from:  Geezer on 13/04/2010 22:14:05
"Can factors that affect my life directly alter the genes that I pass on to my progeny, or are the genes that I pass on to my progeny simply determined by the genes that I inherited from my parents, plus or minus some random transcription errors?"

Sorry I thought you might read the links and decide for yourself.

here is another example:
Alcohol during pregnancy chemically alters fetal DNA
www.newscientist.com/.../dn18390-alcohol-during-pregnancy-chemically-alters-fetal-dna.html -

We are aware today that what we allow our children to do, will effect future generations for example...smoking at early increases the size of their children at birth, sitting in front of the computer for extended long periods, malnutrition, over eating, gambling, where we live, religion, etc, etc does have an ever lasting effect on generations to come, even though it has been established that these inherited traits may jump generations.

Some genetic diseases are carried through the male generation, some female and others both.

I was once told I am more like my gradparent than my direct parent, yet I could be visually mistaken for my cousin.

Maybe, the errors you speak of are just the genes being switch off or on by epigentics regulators?
« Last Edit: 14/04/2010 01:17:16 by echochartruse »
 

Offline JP

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Re: How big a role does the epigenome play in evolution?
« Reply #88 on: 14/04/2010 02:22:06 »
Firstly isn't radiation an environmental/epigentic issue?
You're consistently misunderstanding what epigenetic changes are throughout this thread.  There is some debate as to the subtle points of epigenetics, but it's basically defined as changes to DNA expression that occur without changes to the underlying DNA itself.

Therefore radiation is environmental, and not epigenetic.


Quote
here is another example:
Alcohol during pregnancy chemically alters fetal DNA
www.newscientist.com/.../dn18390-alcohol-during-pregnancy-chemically-alters-fetal-dna.html -
Alcohol is environmental.

All the links you've been posting have been missing the point, since you're confusing epigenetics with non-epigenetic methods that induce changes in DNA.
 

Offline JP

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Re: How big a role does the epigenome play in evolution?
« Reply #89 on: 14/04/2010 02:40:47 »
I just came across this, and I'm not sure if I am understanding or interpreting it correctly:

http://www.ncbi.nlm.nih.gov/pubmed/10690404?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_SingleItemSupl.Pubmed_Discovery_RA&linkpos=3&log$=relatedreviews&logdbfrom=pubmed

Quote
A decade of research on adaptive mutation has revealed a plethora of mutagenic mechanisms that may be important in evolution. The DNA synthesis associated with recombination could be an important source of spontaneous mutation in cells that are not proliferating. The movement of insertion elements can be responsive to environmental conditions. Insertion elements not only activate and inactivate genes, they also provide sequence homology that allows large-scale genomic rearrangements. Some conjugative plasmids can recombine with their host's chromosome, and may acquire chromosomal genes that could then spread through the population and even to other species. Finally, a subpopulation of transient hypermutators could be a source of multiple variant alleles, providing a mechanism for rapid evolution under adverse conditions.

The first part of the underlined section seems to be referring to epigenomic markers.  "Insertion elements not only activate and inactivate genes, they also provide sequence homology that allows large-scale genomic rearrangements." seems to be saying epigenomic markers are responsible for the mechanism which allows an organism to make a large mutation?

"Some conjugative plasmids can recombine with their host's chromosome, and may acquire chromosomal genes that could then spread through the population and even to other species."  This seems to be saying that certain plasmids may be able to "carry" beneficial mutations throughout a population?  If this occurs, mustn't it have evolved at some point?  The only reason I can think of as to why a mutation like that would be beneficial is because it allows beneficial mutations to be transmitted without direct mating.  If that is true, it seems to be just another element which is starting to show us just how advanced life is, and how much it seems to recognize(consciously or not) the need to evolve into a fitter organism is paramount to survival of future generations.

To be honest, I'm not precisely sure what transient hypermutators are specifically, but I'm guessing from the name that they are theoretical cellular "machines" capable of increasing the rate of mutation under adverse conditions. 
They aren't.  Transient hypermutators are cells that mutate quickly when put under selective pressure.  The big question about them is why they happen and why they seem to favor beneficial mutations.  The cited paper on it is here: http://www.genetics.org/cgi/reprint/126/1/5?ijkey=052e053149bad47e2eaa9e5103b0b085358501d3 and gives some explanations (none of them epigenetic).
 

Offline JP

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Re: How big a role does the epigenome play in evolution?
« Reply #90 on: 14/04/2010 03:04:14 »
I'm not sure how you can still assert that there is absolutely no evidence of epigenetically driven genetic mutation, I could understand if you had simply said that you don't feel there is enough evidence(although I disagree obviously), but to simply say there is no evidence at all?

If you are merely stating that it hasn't been proven yet, then I would have to ask how you feel about the standard model of physics?  It hasn't been proven, it has made predictions which have occurred and therefore has gained merit, but it still isn't proven.

Evolution driven by epigenomic markers certainly hasn't been proven, nor does it have as many years or predictions as the standard model has behind its belt; but it does make predictions, and those predictions have been proven.

There are other mechanisms for quick change.  There is also reason enough for me to think (based on my understanding of the subject) that epigenetic induced genetic mutation should occur faster than the observed rates, even when mutation appears to occur faster than expected.  There are proposed non-epigenetic models that do fit this date.  There is also no evidence, based on the way epigenetics works, that it can induce genetic mutations. 

The comparison to the standard model is also flawed.  The standard model predicts the probabilities of seeing certain things when you do certain experiments.  This has been very successfully tested.  As far as I know, and in your arguments here, the prediction made by epigenetics is simply "faster mutations," although it's also missing the step of how it causes those mutations.  There are other explanations for faster mutations that do include that step, so why favor epigenetics?  Have there been any simulations comparing epigenetic mutation to these other explanations that come out favoring epigenetics?
 

Offline echochartruse

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Re: How big a role does the epigenome play in evolution?
« Reply #91 on: 14/04/2010 03:16:07 »

Therefore radiation is environmental, and not epigenetic.


Alcohol is environmental.

All the links you've been posting have been missing the point, since you're confusing epigenetics with non-epigenetic methods that induce changes in DNA.

Quote
author = http://www.newscientist.com/article/dn18390-alcohol-during-pregnancy-chemically-alters-fetal-dna.html

Alcohol during pregnancy chemically alters fetal DNA
This suggests that if women drink too much in pregnancy, epigenetic changes may cause some of the permanent symptoms seen in fetal alcohol syndrome in their children.

Quote
1993 Academic Press -  Delayed Heritable Damage and Epigenetics in Radiation-Induced Neoplastic Transformation of Human Hybrid Cells, by Marc S. Mendonca, Ronald J. Antoniono and J. Leslie Redpath © 1993 Radiation Research Society.
We have reported previously that under identical experimental conditions both the establishment of plateau phase and the onset of the expression of lethal mutations also occur after Day 9. We therefore propose that radiation-induced neoplastic transformation of HeLa × skin fibroblast hybrid cells is a consequence of the delayed expression of heritable damage under epigenetic control with a resultant loss of tumor-suppressor function.

 

Offline echochartruse

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Re: How big a role does the epigenome play in evolution?
« Reply #92 on: 14/04/2010 03:27:38 »
There is also no evidence, based on the way epigenetics works, that it can induce genetic mutations. 

In regard to the links and posts I contributed for this forum about the Tassie Devil....
The genetically modified mono culture planted in the devil's region has caused the tumors.
prior to the TDFT “The majority of devils in Tasmania were immunological clones and therefore susceptible to DFTD,” Geneticist and devil researcher Dr Kathy Belov http://www.tassiedevil.com.au/research.html#different
In 3-5 generations Devil's have genetic diversity changed.

All I can say is that epigenetics controls change and mutations in genes, would you except that?
 

Offline echochartruse

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Re: How big a role does the epigenome play in evolution?
« Reply #93 on: 14/04/2010 03:52:59 »
WHAT IS EPIGENETICS?
The development and maintenance of an organism is orchestrated by a set of chemical reactions that switch parts of the genome off and on at strategic times and locations. Epigenetics is the study of these reactions and the factors that influence them.

EPIGENETICS & THE ENVIRONMENT
The genome dynamically responds to the environment. Stress, diet, behavior, toxins and other factors activate chemical switches that regulate gene expression.
http://learn.genetics.utah.edu/content/epigenetics/

I believe I'm on the right track, Could JP explain my mistake please. Confussed.
 

Offline JP

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Re: How big a role does the epigenome play in evolution?
« Reply #94 on: 14/04/2010 04:17:51 »
Epigenetics does not lead to gene mutations.  You're citing many examples of gene mutations which can be explained by other mechanisms.
 

Offline echochartruse

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Re: How big a role does the epigenome play in evolution?
« Reply #95 on: 14/04/2010 05:27:41 »
Epigenetics does not lead to gene mutations.  You're citing many examples of gene mutations which can be explained by other mechanisms.

So we have established that epigenetics changes the cell's gene expression.
We know they do this by adding and removing mythal tags.(turning on and off genes)and this epigeneome acts as a cellular memory.(tags and records onto DNA)This continues through life and is inherited.

It doesn't have to lead to mutation to make vast alterations or variations in our DNA. But could over time.[quote A large genetic analysis of ethnic Chinese has revealed subtle genetic differences within the world's most populous nation.]

Epigenetics may well be the initiating stage for gene mutation since it controls whether or not the gene is active. over generations of the gene being turned on/off

Remembering that not a single gene mutation has ever benefited life, in my opinion mutation is neither beneficial or necessary for the survival of the fittest.
 

Offline echochartruse

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Re: How big a role does the epigenome play in evolution?
« Reply #96 on: 14/04/2010 05:40:52 »
is skin cancer which is a mutation of the melonomas epigenetic or not and why please so I can understand.
 

Offline JP

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Re: How big a role does the epigenome play in evolution?
« Reply #97 on: 14/04/2010 05:43:00 »
It doesn't have to lead to mutation to make vast alterations or variations in our DNA. But could over time.[quote A large genetic analysis of ethnic Chinese has revealed subtle genetic differences within the world's most populous nation.]
Yes, it does.  Altering DNA itself is a mutation.  Altering the expression of DNA is epigenetics.  Those are the points you're confusing.

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Epigenetics may well be the initiating stage for gene mutation since it controls whether or not the gene is active. over generations of the gene being turned on/off
It certainly may well be, but that makes it a hypothesis to be tested and so far there hasn't been evidence of that.  

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Remembering that not a single gene mutation has ever benefited life, in my opinion mutation is neither beneficial or necessary for the survival of the fittest.
If I'm reading this correctly, your opinion is counter to mainstream science and evidence.  See Geezer's comment above: http://www.thenakedscientists.com/forum/index.php?topic=30685.msg306631#msg306631
 

Offline JP

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Re: How big a role does the epigenome play in evolution?
« Reply #98 on: 14/04/2010 05:48:07 »
is skin cancer which is a mutation of the melonomas epigenetic or not and why please so I can understand.

It could come from a variety of sources, none of which are epigenetic.  Off the top of my head (and from a limited understanding of the cellular processes involved), it is often caused by UV radiation damaging the DNA.  This damaged DNA can then cause the cell to go haywire, causing a cancer.  It could also be caused by transcription errors which occur when a cell copies its DNA.  These errors change the DNA which could then cause a cell to go haywire.

Epigenetic changes occur when a cell wants to turn off the action of a part of the DNA.  It doesn't destroy its DNA, but just says that it should stop following instructions from that part of the DNA.  The DNA itself is still intact and will be copied properly.  Future cells will have the same DNA as their parent (unless one of the other processes for DNA damage occurs).  The cells shouldn't go haywire since there's no error in the DNA that would make them do so.

At the very least, what I'm saying throughout is that there is no evidence that epigenetic processes can damage or change DNA in the same way as radiation or transcription errors.
 

Offline echochartruse

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Re: How big a role does the epigenome play in evolution?
« Reply #99 on: 14/04/2010 05:56:30 »
If I'm reading this correctly, your opinion is counter to mainstream science and evidence.  See Geezer's comment above: http://www.thenakedscientists.com/forum/index.php?topic=30685.msg306631#msg306631

Please explain one mutation that is benefitual to life. I can't find one.
 

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Re: How big a role does the epigenome play in evolution?
« Reply #99 on: 14/04/2010 05:56:30 »

 

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