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Lamarck was right: How epigenetic memory is passed through generations

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C. elegans embryos show inheritance and transmission of an epigenetic mark. /Laura J. Gaydos

From ScienceDaily:

A growing body of evidence suggests that environmental stresses can cause changes in gene expression that are transmitted from parents to their offspring, making “epigenetics” a hot topic. Epigenetic modifications do not affect the DNA sequence of genes, but change how the DNA is packaged and how genes are expressed. Now, a study by scientists at UC Santa Cruz shows how epigenetic memory can be passed across generations and from cell to cell during development. /blockquote>

Strome noted that the findings in this study of transmission of histone methylation in C. elegans have important implications in other organisms, even though different organisms use the repressive marker that was studied to regulate different genes during different aspects of development. All animals use the same enzyme to create the same methylation mark as a signal for gene repression, and her colleagues who study epigenetics in mice and humans are excited about the new findings, Strome said.

“Transgenerational epigenetic inheritance is not a solved field–it’s very much in flux,” she said. “There are dozens of potential epigenetic markers. In studies that document parent-to-child epigenetic inheritance, it’s not clear what’s being passed on, and understanding it molecularly is very complicated. We have a specific example of epigenetic memory that is passed on, and we can see it in the microscope. It’s one piece of the puzzle.”

Here’s the abstract:

For proper development, cells must retain patterns of gene expression and repression through cell division. Repression via methylation of histone H3 on Lys27 (H3K27me) by Polycomb repressive complex 2 (PRC2) is conserved, but its transmission is not well understood. Our studies suggest that PRC2 represses the X chromosomes in Caenorhabditis elegans germ cells, and this repression is transmitted to embryos by both sperm and oocytes. By generating embryos containing some chromosomes with and some without H3K27me, we show that, without PRC2, H3K27me is transmitted to daughter chromatids through several rounds of cell division. In embryos with PRC2, a mosaic H3K27me pattern persists through embryogenesis. These results demonstrate that H3K27me and PRC2 each contribute to epigenetically transmitting the memory of repression across generations and during development. – L. J. Gaydos, W. Wang, S. Strome. H3K27me and PRC2 transmit a memory of repression across generations and during development. Science, 2014; 345 (6203): 1515 DOI: 10.1126/science.1255023 (paywall)

Note: From a Darwinsite:

Lamarck’s scientific theories were largely ignored or attacked during his lifetime; Lamarck never won the acceptance and esteem of his colleagues Buffon and Cuvier, and he died in poverty and obscurity. Today, the name of Lamarck is associated merely with a discredited theory of heredity, the “inheritance of acquired traits.” However, Charles Darwin, Lyell, Haeckel, and other early evolutionists acknowledged him as a great zoologist and as a forerunner of evolution.

So why did Darwin’s followers have to denigrate Lamarck. Wonder what they will say now as he turns out to be right?

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wd400, Uh oh. See #7. ;-) -Q Querius
I encourage anyone who thinks this means "Lamarck was right" to go an learn what Lamarck claimed. Modern epigenetics is much more like (but still different than) Darwin's pangenes than any of Lamarck's mysticism. wd400
A_B how do you define short term or long term? Is short only <5 generations? More? Less? Dr JDD
Mung wrote
Am I the only one here who does not find epigenetics to be the revival of Lamarkism?
Indeed, Lamarck didn't have a mechanism to account for what appears to be novel inherited change . . . but then neither did Darwin. Where do you want to draw the line? One can object to crediting Lamarck with the idea, but many ideas were preceded by Greek philosophers anyway. It's a stretch, but if the right environment is present to account for the OOL, would we give Von Helmont the credit? I guess it would be more correct to say that the interaction of epigenetic information in organisms is closer to Lamarck's views than Darwin's. It would not be correct to say that "Lamarck was right after all" unless Lamarck had data to back up his ideas. -Q Querius
Mung: "Am I the only one here who does not find epigenetics to be the revival of Lamarkism?" No. Only a moron would think this. Lamarkism was about the long term inheritance of acquired characteristics, the proverbial giraffe's neck argument. Epigenetics is, at best, the extremely short termed inheritance of stress induced phenotypic changes, many of them deleterious to survival. Nobody is seriously suggesting that this can result in permanent change. After all, fetal alcohol syndrome is epigenetic. Acartia_bogart
Have they shown that a giraffe can grow a longer neck during it’s lifetime so that it can reach taller trees and then pass that aquired trait on via epegenitcs?
No. But they have shown that finches can grow longer or shorter beaks in response to their environment. It's all epigenetics, I'm sure. Mapou
I keep having to remind myself that News may be over-sensationalizing in order to spark debate. Let my try a different route. Am I the only one here who does not find epigenetics to be the revival of Lamarkism?
The evolutionary biologist T. Ryan Gregory has written that epigenetic inheritance should not be considered "Lamarckian". According to Gregory; Lamarck did not claim the environment imposed direct effects on organisms, instead Lamarck "argued that the environment created needs to which organisms responded by using some features more and others less, that this resulted in those features being accentuated or attenuated, and that this difference was then inherited by offspring." Gregory has stated that "Lamarckian" evolution in the context of epigenetics is actually closer to the view held by Darwin rather than by Lamarck. - http://en.wikipedia.org/wiki/Lamarckism#Epigenetics
I don't know, Mung. But I do remember in high school biology being annoyed at being taught about the "experiment" that supposedly disproved Lamarck by cutting of the tails of mice for umpteen generations without any measured reduction in the following generation of mice. Pathetic. See Tails of Mice, Ears of Dogs http://www.textbookleague.org/54marck.htm Comedy relief http://www.answers.com/Q/How_did_weismann_disprove_lamarck%27s_theory There's nothing as doctrinaire as a schoolteacher--you know, the "choose the best answer" type. -Q Querius
Have they shown that a giraffe can grow a longer neck during it's lifetime so that it can reach taller trees and then pass that aquired trait on via epegenitcs? Mung
OT: I would like to touch on another aspect of Darwinian theory that has failed. Recently, Dr. Wells did a video, wrote a paper, and did a podcast, on the failure of the central dogma of neo-Darwinism to give an adequate explanation for 'form', i.e. body plans.
Body Plans Are Not Mapped-Out by the DNA - Jonathan Wells - video http://www.youtube.com/watch?v=meR8Hk5q_EM podcast - Dr. Jonathan Wells: Biology’s Quiet Revolution - September 17, 2014 http://www.discovery.org/multimedia/audio/idtf/2014/09/dr-jonathan-wells-biologys-quiet-revolution/ On this episode of ID the Future, Dr. Jonathan Wells discusses a popular claim, which he describes as “DNA makes RNA makes protein makes us”—or, every organism contains a program for itself in its DNA. Though this view fits neatly with the perspective of Darwinian evolution, it has been shown to be incorrect at every step. Listen in as Dr. Wells explains. Biology's Quiet Revolution - Jonathan Wells - September 8, 2014 Excerpt: In 1996, biologists discovered a protein that does not fold into a unique shape but can assume different shapes when it interacts with other molecules. Since then, many such proteins have been found; they are called "intrinsically disordered proteins," or IDPs. IDPs are surprisingly common, and their disordered regions play important functional roles.,,, So it is not true that biologists know all the basic features of living cells and are merely filling in the details. Nor is it true that Darwinian evolution is a settled scientific "fact," as its defenders claim. Huge unanswered questions remain, and they will only be answered by going beyond the discredited myth that "DNA makes RNA makes protein makes us." http://www.evolutionnews.org/2014/09/biologys_quiet_089651.html
Stuart A. Newman puts the failure of neo-Darwinism to explain 'form' like this,,,
The Gene Myth, Part II - August 2010 Excerpt: “It was long believed that a protein molecule’s three-dimensional shape, on which its function depends, is uniquely determined by its amino acid sequence. But we now know that this is not always true – the rate at which a protein is synthesized, which depends on factors internal and external to the cell, affects the order in which its different portions fold. So even with the same sequence a given protein can have different shapes and functions. Furthermore, many proteins have no intrinsic shape, taking on different roles in different molecular contexts. So even though genes specify protein sequences they have only a tenuous (very weak or slight) influence over their functions. ,,,,So, to reiterate, the genes do not uniquely determine what is in the cell, but what is in the cell determines how the genes get used. Only if the pie were to rise up, take hold of the recipe book and rewrite the instructions for its own production, would this popular analogy for the role of genes be pertinent. Stuart A. Newman, Ph.D. – Professor of Cell Biology and Anatomy http://darwins-god.blogspot.com/2010/08/gene-myth-part-ii.html
This failure of the central dogma of neo-Darwinism to explain form extends to the 3 dimensional structure of DNA itself,,,
Getting Over the Code Delusion (Epigenetics) - Talbot - November 2010 Excerpt: The standard doctrine has it that functionally important sequences, precisely because they are important to the organism, will generally be conserved across considerable evolutionary distances. But the emerging point of view holds that architecture can matter as much as sequence. As bioinformatics researcher Elliott Margulies and his team at the National Human Genome Research Institute put it, “the molecular shape of DNA is under selection” — a shape that can be maintained in its decisive aspects despite changes in the underlying sequence. It’s not enough, they write, to analyze “the order of A’s, C’s, G’s, and T’s,” because “DNA is a molecule with a three-dimensional structure.”[14] Elementary as the point may seem, it’s leading to a considerable reallocation of investigative resources. http://www.thenewatlantis.com/publications/getting-over-the-code-delusion
Stephen Meyer comments on the failure of neo-Darwinism to explain 'form' here,,,
Stephen Meyer - Functional Proteins And Information For Body Plans - video https://vimeo.com/91322260 Dr. Stephen Meyer comments at the end of the preceding video,,, ‘Now one more problem as far as the generation of information. It turns out that you don’t only need information to build genes and proteins, it turns out to build Body-Plans you need higher levels of information; Higher order assembly instructions. DNA codes for the building of proteins, but proteins must be arranged into distinctive circuitry to form distinctive cell types. Cell types have to be arranged into tissues. Tissues have to be arranged into organs. Organs and tissues must be specifically arranged to generate whole new Body-Plans, distinctive arrangements of those body parts. We now know that DNA alone is not responsible for those higher orders of organization. DNA codes for proteins, but by itself it does not insure that proteins, cell types, tissues, organs, will all be arranged in the body. And what that means is that the Body-Plan morphogenesis, as it is called, depends upon information that is not encoded on DNA. Which means you can mutate DNA indefinitely. 80 million years, 100 million years, til the cows come home. It doesn’t matter, because in the best case you are just going to find a new protein some place out there in that vast combinatorial sequence space. You are not, by mutating DNA alone, going to generate higher order structures that are necessary to building a body plan. So what we can conclude from that is that the neo-Darwinian mechanism is grossly inadequate to explain the origin of information necessary to build new genes and proteins, and it is also grossly inadequate to explain the origination of novel biological form.’ Stephen Meyer - (excerpt taken from Meyer/Sternberg vs. Shermer/Prothero debate - 2009) Darwin's Doubt narrated by Paul Giem - The Origin of Body Plans - video http://www.youtube.com/watch?list=PLHDSWJBW3DNUaMy2xdaup5ROw3u0_mK8t&v=rLl6wrqd1e0&feature=player_detailpage#t=290
What should be needless to say, this IS NOT a minor criticism against neo-Darwinism but is a criticism that pulls neo-Darwinian theory out by its roots. bornagain77

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