The Koala, Lamark and Epigenetics

The late Farrell Till said that the koala has a very narrow diet; infact some are so specialized that they not only can't eat anything but eucalyptus leaves but they also cannot eat from eucalyptus trees outside their local eucalyptus woods (or something like that).https://www.youtube.com/watch?v=vnK4dTtX8L0Could a bunch of random DNA mutations explain the koala diet. I'm asking if the "neo-Darwinian" theory (using Gregor Mendel theory to supplement Darmin's theory) really does best explain this situation. Wouldn't the data suggest that the most logical conclusion is that this narrow diet was acquired by behavior of a koala during his/her life and somehow (by say epigenetic means?) this trait got passed down into succeeding offspring and it got locked into the animals DNA later down the generational tree?Humans used to not be able to digest cow milk until around 6,000 to 10,000 years ago. Now 96% of Sweedish people can digest cow milk. Random DNA mutations brought this about?Perhaps Lamark might have been onto something. Or no?Edited by Admin, : Change title from "Does the narrow quala diet back up Lamark's 1809 theory?" and fix spelling.

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LamarkNewAge
... Wouldn't the data suggest that the most logical conclusion is that this narrow diet was acquired by behavior of a koala during his/her life and somehow (by say epigenetic means?) this trait got passed down into succeeding offspring and it got locked into the animals DNA later down the generational tree? ...
RAZD
My first impression is that modern evolutionary theory is sufficient. There are many example where plants evolve with specific animals\insects\etc to mutual benefit: the plant gets fertilized or seeds distributed in exchange for providing a special diet, and the consumer gets special food in exchange for assisting the plant to grow (fertilizer) and spread.

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The symbiotic aspect to the koala/eucalyptus relationship can be explained by standard evolutionary theory.I also mentioned the lactose issue.Dr. Adequate linked me to Wikipedia and it had this text on the linked page.

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Lactase expression persistence is largely due to natural selection, which is a component of evolution by which a trait affects the chances of the survival of organisms, and consequently, the trait becomes more prevalent in the population over time.

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The ability to digest lactose is not an evolutionary novelty in human populations. Nearly all mammals begin life with the ability to digest lactose. This trait is advantageous during the infant stage, because milk serves as the primary source for nutrition. As weaning occurs, and other foods enter the diet, milk is no longer consumed. As a result, the ability to digest lactose no longer provides a distinct fitness advantage.[12] This is evident in examining the mammalian lactase gene (LCT), which decreases in expression after the weaning stage, resulting in a lowered production of lactase enzymes.[12] When these enzymes are produced in low quantities, lactose non-persistence (LNP) results.[13]

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So mammals already have the nearly universal (?) ability to digest milk at birth. "Lactase persistence" is the ability to digest it into adulthood. That issue seems to be an evolutionary adaption tied to a life or death need to get vitamin D in the diet. Mainly a trait brought to Europeans that were isolated in a way that prevented their access to fish, I suppose. Darwinian mechanics do indeed explain this one.Then the next issue.

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LamarkNewAge
Could a bunch of random DNA mutations explain the koala diet. I'm asking if the "neo-Darwinian" theory (using Gregor Mendel theory to supplement Darmin's theory) really does best explain this situation. ...
RAZD
Yes, because evolution involves selection as well as random variation.

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What I don't see is a reason to assume a neo-lamarkian explanation, why the data would suggest the diet isolation would be an acquired trait. Can you explain your thinking here?

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What would be the environmental chemical that would cause this and what would be the source for it?

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It seems this quote is the response to the issue of the extraordinary limits in the koala diet. It's a good question you ask and I am not qualified to present the solution. But the problems presented to a neo-Darwinian solution are also quite large. A random mutation (or series of mutations) that lead to such a narrow diet that by coincidence only enables digestion of a single type of plant just doesn't seems to fit what must go on in nature (so my thinking goes anyway).I think of the brain as possibly being similar to a floppy disc where information can be learned in life then passed on to generations. In biology, there seems to be epigenetic inheritance based on stressful experiences during life (such as the loss of hair being passed on to children or belly fat brought on by stress induced cortisol). The issue is how can such dietary-digestion issues come about from 100% random mutations when the loss of such ability doesn't seem to happen in our lives or the lives of the 7 billion people alive today. But perhaps there is a Lamarkian explanation to these things.I don't have the solution though. I'm interested in exploring the problems to Darwinian explanations and the evidence that might back up Lamarkian solutions to other issues and possibly this issue.

Bad because the ability was already almost there to start with -even 10,000 years ago.The issue of the Koala diet however is more complicated.

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LamarkNewAge
... A random mutation (or series of mutations) that lead to such a narrow diet that by coincidence only enables digestion of a single type of plant just doesn't seems to fit what must go on in nature (so my thinking goes anyway). ...

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RAZD
Again you are forgetting selection. Selection is non-random, and it is the other part of evolution that leads to adaptation.

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Selection for an animal going blind happens when the animal species will live in a (nearly or)100% dark environment. It takes a lot of molecular energy for eyes to (be able to) see so selection can and does lead to that gene-for-seeing getting turned off in increasingly large numbers of the species over time.But how can 1 million different types of food to possibly eat(represented in an animal by 1 million hypothetical genetic variants) out of 1,000,001 genetic variant possibilities in time get driven out of the gene pool of an animal. I know it CAN HAPPEN according to neo-Darwinian theory but how DOES it happen in practice? Eventually, the molecular mutations won't do what they might be capable of. They can but won't keep on eliminating all the various DNA codes except the one that allows just one (!) type of food to eat. I agree that it might be molecularly efficient and AGAIN I agree that it is genetically possible.(Lamarkian?) Epigenetics is far faster than the lone neo-Darwinian mechanism and might follow a pattern in nature we can picture if we imagine how a chicken learned how to cross the street (it just learned!). How do migratory birds know where to fly (even if their parents weren't around to teach them)? How do we learn anything? Random mutations? We just learn.

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Tanypteryx
We have been studying biology for a couple hundred years at increasingly fine detail. We are at the stage where we observing life at the molecular level and in all that time millions of scientists have not identified any mechanism or effect that we would define as Lamarkian.

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Well, Lamark didn't have at his disposal knowledge of Gregor Mendel nor many other developments that came out long ago, so a confirmation of raw-Lamark theory wouldn't exactly be expected.

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Tanypteryx
There have been no discoveries that do not fit with evolutionary theory. Think about it, not one single observation refutes evolutionary theory.

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The theory of Erasmus Darwin? Lamark? Or any of the early founders pre-Charles Darwin?Even I wouldn't go that far but I still predict Lamark will carry the day!

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Tanypteryx
If you looked up the biology of koala and eucalyptus I think you will find that it has been studied in exquisite detail and is quite satisfactorily explained without resorting to some unknown undefined mechanism that has escaped notice before.

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The koala and its digestion ability is the extraordinary issue here I am interested in.

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Tanypteryx
We have moved far beyond Darwinian explanations today. They are still important, but our understanding has been expanded considerably. Any problems to Darwinian explanations that may have existed have been thoroughly studied and corrected long ago.

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I was under the impression that the discovery of epigenetics has been something of a revelation and an ongoing horizon of great scientific intrigue. You are somewhat contradicting yourself in this post.

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Tanypteryx
Can you describe what a Lamarkian solution might be, and how it could have escaped our notice until now?

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Perhaps examples of 2 animals with "identical" DNA nevertheless having significant differences with each other through epigenetic expressions can count as somewhat "Lamarkian". I don't know what the best terminology is. This isn't going to be a 100% raw-lamark 1809 solution though (if there even are "Lamarkian" solutions).

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RAZD

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Well, again, turning to Wikipedia, I read this:

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Koalas are herbivorous, and while most of their diet consists of eucalypt leaves, they can be found in trees of other genera, such as Acacia, Allocasuarina, Callitris, Leptospermum, and Melaleuca. [...] Despite its reputation as a fussy eater, the koala is more generalist than some other marsupial species, such as the greater glider.

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So using Lamarckism to explain why it only eats a single type of plant is invoking a mechanism that wouldn't work to explain a fact that isn't true.

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Mr. Till seemed to suggest that some do have a more limited ability to digest food than others. Not all but some. I wish he was still around so we could email him and ask for specifics.---

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RAZD
As to whether the lactose issue is a good one, I think it's an excellent one because we have the data. We have humans with lactase persistence, and then members of the same species that don't have it, and we have studied the genes of our own species so thoroughly that we know at the nucleotide level exactly what makes the difference. By contrast, the koala is the sole surviving member of its family, its nearest relatives are wombats, and the genome of neither the koala nor the wombat has been sequenced. This leaves the field wide open for speculation about Lamarckian epigenetics and the diet of koalas. Whereas in the case of humans and lactose, we know. It's a test case that we can actually test and not just speculate about. And when we put it to the test it has nothing to do with epigenetics

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But keep in mind that those who argue for a "Lamarkian" epigenetics suggest that DNA changes come (in time)but only after epigenetics paved the way first. I remember reading a Seed Magazine (a subscription I had in 2006 to a scientific publication and I'm not even sure if it is still around) from 2006 (?) where they made a good case.The lactose variations were already were very present in the human genetic code. I was drawing an analogy that wasn't the best one.

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LamarkNewAge
I think of the brain as possibly being similar to a floppy disc where information can be learned in life then passed on to generations.

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NoNukes
In the case of mammals, there are plenty of more conventional methods for passing along information. Mammals tend to spend time hanging out with mama which means that behavioral information can be passed on by teaching/learning.

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Assuming a brain is a floppy disk, what part of that disk could possible be passed on genetically or even via epigenetics? What is the mechanism?

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It seems that there are non-DNA expressions at work.I have been thinking of using the example of a human breeding foxes so that by the 26th generation, all in a breed we able to respond to the "sit" command when none could at first. But Darwinian theory supporters will just say the genetic information "was there to start with" or some DNA change (or some "standard theory" change) can be explained.Will we still be saying that 100 years from now?

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LamarkNewAge
(Lamarkian?) Epigenetics is far faster than the lone neo-Darwinian mechanism

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Dr. Adequate
But an epigenetic hypothesis only defers the Darwinian question.

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Epigenetic Lamarckism works like this, as I understand it. You have, external to the DNA, a switch, a toggle, affecting DNA expression. The position of the switch is inherited, but can be flipped as a response to the environment.

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So, let's imagine an epigenetic explanation for the koala diet. What we would need is some sort of switch that toggles between eating like a wombat and eating like a koala, which is flipped into koala mode by some exterior stimulus such as, I dunno, smelling eucalyptus. OK, we now have a nice simple explanation for how and why koalas eat eucalyptus. But we have also saddled ourselves with rather difficult problem: how did the two dietary options and the switch between them evolve? So we haven't really made things any simpler.

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I was thinking something more along the lines of the animals choosing to eat a narrow diet for like 7000 years(while still having the ability to digest thousands of things) but eventually loosing the ability to digest the other things at the end of the (say) 7000 year period. But not through mutations (at least not at first and possibly no mutations at all).---

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Dr. Adequate

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Imagine an alien who thinks that humans are stupid. So when he finds a bicycle, he declares that it's way too sophisticated to have been designed and built by humans unaided. No, he explains, it must have been designed and built by some sort of industrial robot, and all the poor dumb humans did was perform the relatively simple task of pushing the big red ON button on the front of the robot --- and pushing buttons, he smugly explains, is well within their primitive capacities ...

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Well, he hasn't made things any easier for himself, has he? Because now he needs to explain how those dumb humans who're too stupid to build a mere bicycle managed to produce the robot.

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I think "learning" brings about self-organization at the biological level. Information is added then much of it gets lost in time. But DNA doesn't tell the whole story.

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Tanypteryx
I think there is a misunderstanding here. I am saying that the modern Theory of Evolution includes all the knowledge about biology we have today. It does not include theories that have been shown to be invalid and there have been no observations that have been shown to be valid that refute the ToE. Not one.

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People reading your posts will be confused about what I am actually saying. And that would be true even if you fully quoted me in context. It is even more true without in-context and complete quotes.Anyway, the general issue of "evolution" I have not disputed. I'm just saying that a heck of a lot is still to be discovered. Disagree with that? Well, the chemistry-to-biology transition (i.e. origin of life and self-replicating peptide bonded amino acids type issues) doesn't even have a theory yet. So whatever hypothesis one picks, it will be monumentally revised once the discovery is finally made.We can all agree on that. However, I would suggest that the biological evolution issue will also be subject to enormous revisions.But many of my quotes centered around you changing the subject from the issue of general evolution to the issue of Lamarkian-type evolution to Darwinian evolution in a somewhat chaotic way.Just thought I would clarify.Edited by LamarkNewAge, : No reason given.

Mice Inherit Specific Memories, Because Epigenetics?

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Mice Inherit Specific Memories, Because Epigenetics?
Posted Sun, 12/1/2013

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Two weeks ago I wrote about some tantalizing research coming out of the Society for Neuroscience meeting in San Diego. Brian Dias, a postdoctoral fellow in Kerry Ressler’s lab at Emory University, had reported that mice inherit specific smell memories from their fathers even when the offspring have never experienced that smell before, and even when they’ve never met their father. What’s more, their children are born with the same specific memory.

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This was a big, surprising claim, causing many genetics experts to do a double-take, as I discovered from a subsequent flurry of Tweets. Crazy Lamarkian shit, quipped Laura Hercher (@laurahercher), referring to Lamarckian inheritance, the largely discredited theory that says an organism can pass down learned behaviors or traits to its offspring. My instinct is deep skepticism, but will have to wait for paper to come out, wrote Kevin Mitchell (@WiringTheBrain). If true, would be revolutionary.

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The paper is out today in Nature Neuroscience, showing what I reported before as well as the beginnings of an epigenetic explanation. (Epigenetics usually refers to chemical changes that affect gene expression without altering the DNA code).

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Having the data in hand allowed me to fill in the backstory of the research, as well as gather more informed reactions from experts in neuroscience and in genetics. I’ve gone into a lot of detail below, but here’s the bottom line: The behavioral results are surprising, solid, and will certainly inspire further studies by many other research groups. The epigenetic data seems gauzy by comparison, with some experts saying it’s thin-but-useful and others finding it full of holes.

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MORE (much more in link)This study took great care to implement controls to preclude the possibility of social transmission. This study could indicate biological programming based on acquired characteristics.

GoogleHere is a google link (I didn't check the "news" part yet) to web hits based on this.EDIT (here is top "news" item link and it is interesting)
Epigenetic Change: Lamarck, Wake Up, You’re Wanted in the Conference Room! | Evolution News(here is other 2015 story in "news" under my search words above
Study of Holocaust survivors finds trauma passed on to children's genes | Genetics | The GuardianThis is the best "evidence" I have so don't expect much else from me lol.Thanks to the posters who responded to me so far. Much appreciated. God bless EVC and the great posters. I hope this great site lasts another 15 years.FINAL EDIT I found that Seed magazine (website) I subscribed to from around 2005-2008 (no longer in print I'm sorry to say) but the c. 2006 article isn't there. I think this 2009 article is from the same author though. It is very similar. I really appreciated the 2006 article because it was the first time I saw scientific evidence for Lamarkian views that I always suspected were true since I was in my early teens. I never thought I would see the day!
http://seedmagazine.com/...nt/article/extending_darwinism/P2Edited by LamarkNewAge, : "news" linkEdited by LamarkNewAge, : No reason given.

Your question was complex and my response was simple to be sure. (I was ashamed of such a sorry response, at the time of posting, and you quoted the paragraph of my greatest shame in this thread)SIDE NOTE.I also must admit that I have been partly motivated by New Age type of issues. I have had a vague exposure to Hindu and Zoroastrian ideas (heaven, hell, judgment day, afterlife)for a long time but never have really studied the issues much. The language of the Gathas and Vedas are dated from 1500-1800 BCE and are the oldest Indo-European texts. The Zoroastrians have a New Age type of situation (in texts later than the Gathas but before 2 Isaiah and Daniel) where man stops eating meat, then plants, then water. Then the 3000 year Judgment Day begins (Revelation 20 is pure Zoroastrian, right down to the detail of Satan/ Angra Mainyu being thrown in the pit with the evil angels for 1000 years though it is 3000 in Zoroastrian). An evolution into spiritual creatures comes first then Judgment Day. Isaiah 40-48 and later chapters take the New Age evolution concept and Daniel even has a resurrection in the Hebrew Bible (The conservative Jewish Temple authorities didn't consider Daniel to be a Prophet but just "wisdom literature" and the definitive statements against a resurrection outnumbered the lone exception so the conservative Sadducees considered the Pharisees to be Persians or Zoroastrian/Jewish hybrids in their acceptance of the resurrection ).The 7000 year cycle of Zoroastrians before Judgment Day (involving vegetarian stages) was partly on my mind lol. But the issue of not being able to digest meat was no more prominent in my thinking than the roughly 7000 years of the gain in ability to digest lactose (gut bacteria might play a role I suppose but I'm not big on the scientific details as I'm just not up to speed, so my responses on the exact way and mechanisms I will avoid).On the science side, I have LONG felt that memories (especially traumatic ones, but not only) can be hard-wired into a species. Perhaps even before I was a teenager. And I admit that it was "simple, common sense" hunch but perhaps partly based on observation of animals.I just never expected that there would be such decent evidence coming in from the scientific side. Honestly, I was just amazed almost 10 years ago when I saw that Seed article. Previously, I automatically wrote off, in my mind, any slight look at "new age" type of evidence. I just didn't think it would get 1 second of coverage by serious scientists though I felt it should.I'm still in shock.

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Dr. Adequate
Imagine an alien who thinks that humans are stupid. So when he finds a bicycle, he declares that it's way too sophisticated to have been designed and built by humans unaided. No, he explains, it must have been designed and built by some sort of industrial robot, and all the poor dumb humans did was perform the relatively simple task of pushing the big red ON button on the front of the robot --- and pushing buttons, he smugly explains, is well within their primitive capacities ...

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Well, he hasn't made things any easier for himself, has he? Because now he needs to explain how those dumb humans who're too stupid to build a mere bicycle managed to produce the robot.

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LamarkNewAge
I think "learning" brings about self-organization at the biological level. Information is added then much of it gets lost in time. But DNA doesn't tell the whole story.

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With evidence coming in that learning can be an acquired characteristic, one has to wonder if there was a quasi-brain in early life forms 4 billion years ago. I was amazed when a friend told me that she worked for an organization that actually trained Octopi to disarm bombs. I was shocked that an animal with no "brain" could do such a thing. The conversation started when she was telling me how smart her per lizard was, and I told her how small the reptile brains were and how amazing it was.Which came first; the brain or the thoughts? Did epigenetic information help the learning to start with? Did the (specific)biological matter come second? Did the DNA follow Lamarckian type of events like epigenesist?Sociologists (trained in history, anthropology, and psychiatry as part of their degree) have long had theories of a "racial memory" which seemed "acquired" (that ugly word to the hard-nosed scientists).The scientific evidence needs to be built up and careful controls are needed but preliminary data show us that the scientists themselves are catching up with the common horse-sense many of us possessed long ago. I know for a fact that at age 14, I felt our brain was somewhat like a floppy disk (all were writable when CD's were "ROM"- Read Only Memory- for a while) and that animal offspring were like a floppy being copied.The dominant view is still that the meat and bones DNA came first then mutated the brain and its thought abilities came later through slow, random mutations. But do DNA changes and the mutations that cause it follow something that already was there to start with. Do biomes (gut bacteria) come first and influence our diet and then the DNA catches up later after the dietary changes? Does RNA and epigenetics come first and then DNA changes come 2nd in many cases?The possibility must be considered.

Does is come from:1 a random mutation that turns on the fear gene if the senses detect a serpent?
(if so then selective breeding, by a geneticist qualified to detect the mutation in the gene code, will pass the trait to offspring OR slow "natural-selection" will kill off those without the mutation - especially/only if serpents are part of the environment, and those with the beneficial mutation will eventually predominate)or2 a member of a specie "learning" to fear a serpent then making sure it teaches the successive offspring the same "fear" generation after generation so that this social transmission becomes a characteristic of each specimen in the species except in rare circumstances?(if so then an extremely careful and controlled experiment can figure out a way to reproduce an offspring while preventing social-contact of any sort with the parent)NOWThe above biological transmission (#1) and social transmission (#2) both are within the neo-Darwinian theory and would not require a "Lamarckian" interpretation.BUT pay attention to the #2 sentence in parentheses. Notice that I did not say what the result will show. That remains to be seen. Stay tuned.
.............................................See my posts 26 and 27.
Mice Inherit Specific Memories, Because Epigenetics?Edited by LamarkNewAge, : No reason given.

I'm glad EVC doesn't delete post material after so many months or years. After15 years, it seems everything stays put). I can always reference this post of yours (if) whenever I have access to JSTOR.PDFs don't work with my computer though. If the pasting option is available, perhaps you can quote a few paragraphs? No problem if you cant.Thanks for those links. Some day I will download them.