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Early life experiences influence DNA in adult brain


File:DNA simple.svg From Salk News:

“We are taught that our DNA is something stable and unchanging which makes us who we are, but in reality it’s much more dynamic,” says Rusty Gage, a professor in Salk’s Laboratory of Genetics. “It turns out there are genes in your cells that are capable of copying themselves and moving around, which means that, in some ways, your DNA does change.”

For at least a decade, scientists have known that most cells in the mammalian brain undergo changes to their DNA that make each neuron, for example, slightly different from its neighbor. Some of these changes are caused by “jumping” genes—officially known as long interspersed nuclear elements (LINEs)—that move from one spot in the genome to another. In 2005, the Gage lab discovered that a jumping gene called L1, which was already known to copy and paste itself into new places in the genome, could jump in developing neuronal brain cells.

The team had hypothesized that such changes create potentially helpful diversity among brain cells, fine-tuning function, but might also contribute to neuropsychiatric conditions.

“While we’ve known for a while that cells can acquire changes to their DNA, it’s been speculated that maybe it’s not a random process,” says Tracy Bedrosian, a former Salk research associate and first author of the study. “Maybe there are factors in the brain or in the environment that cause changes to happen more or less frequently.” More.

Not what we were led to expect by adherents to the Central Dogma.

See also: Comparing human and chimp DNA, using a software analogy


Epigenetic change: Lamarck, wake up, you’re wanted in the conference room!

I don’t think environmental factors influence the flow of sequence information from nucleic acids to proteins.
Of course they do. They can stop the flow or allow the flow to happen. ET
I don't think environmental factors influence the flow of sequence information from nucleic acids to proteins. Your examples in 8 are all about gene expression or the shape of proteins (I guess you are thinking of prions when you say 'heredity by contact'?), not about sequence information. But I'm really more interested in how someone that runs the "News" account a website cannot claim the central dogma is false without even going as far reading the link she uses to describe it (much less understanding what the central dogma actually claims). cornu
The Central Dogma. This states that once 'information' has passed into protein it cannot get out again. In more detail, the transfer of information from nucleic acid to nucleic acid, or from nucleic acid to protein may be possible, but transfer from protein to protein, or from protein to nucleic acid is impossible. Information means here the precise determination of sequence, either of bases in the nucleic acid or of amino acid residues in the protein. Crick 1958
I don’t see how the observations in the OP change this at all. Allan Keith
If the link above is correct then:
The central dogma of molecular biology explains the flow of genetic information, from DNA ?to RNA?, to make a functional product, a protein?.
is incorrect/ incomplete as environmental factors have a say in the flow of information. ET
Yes, those are all things they have nothing to do with central dogma... So what? cornu
It certainly doesn't say that the environment has such an influence over gene expression, heredity by contact and development ET
What do you think the central dogma of molecular biology says? It certainly doesn't say mutations are impossible, or that mutation rates can't differ with regard to environment... cornu
LoL! Determining sex is not the same as determining form. Try again ET
Reference for what? Where’s your reference?
https://www.ncbi.nlm.nih.gov/books/NBK9989/ Allan Keith
Reference for what? Where's your reference? Read "Why is a fly not a horse?" And then we have:
To understand the challenge to the “superwatch” model by the erosion of the gene-centric view of nature, it is necessary to recall August Weismann’s seminal insight more than a century ago regarding the need for genetic determinants to specify organic form. As Weismann saw so clearly, in order to account for the unerring transmission through time with precise reduplication, for each generation of “complex contingent assemblages of matter” (superwatches), it is necessary to propose the existence of stable abstract genetic blueprints or programs in the genes- he called them “determinants”- sequestered safely in the germ plasm, away from the ever varying and destabilizing influences of the extra-genetic environment. Such carefully isolated determinants would theoretically be capable of reliably transmitting contingent order through time and specifying it reliably each generation. Thus, the modern “gene-centric” view of life was born, and with it the heroic twentieth century effort to identify Weismann’s determinants, supposed to be capable of reliably specifying in precise detail all the contingent order of the phenotype. Weismann was correct in this: the contingent view of form and indeed the entire mechanistic conception of life- the superwatch model- is critically dependent on showing that all or at least the vast majority of organic form is specified in precise detail in the genes. Yet by the late 1980s it was becoming obvious to most genetic researchers, including myself, since my own main research interest in the ‘80s and ‘90s was human genetics, that the heroic effort to find information specifying life’s order in the genes had failed. There was no longer the slightest justification for believing there exists anything in the genome remotely resembling a program capable of specifying in detail all the complex order of the phenotype. The emerging picture made it increasingly difficult to see genes as Weismann’s “unambiguous bearers of information” or view them as the sole source of the durability and stability of organic form. It is true that genes influence every aspect of development, but influencing something is not the same as determining it. Only a small fraction of all known genes, such as the developmental fate switching genes, can be imputed to have any sort of directing or controlling influence on form generation. From being “isolated directors” of a one-way game of life, genes are now considered to be interactive players in a dynamic two-way dance of almost unfathomable complexity, as described by Keller in The Century of The Gene- Dr. Michael Denton “An Anti-Darwinian Intellectual Journey”, Uncommon Dissent (2004), pages 171-2
Allan, we do not know what determines form. That means we do not know if the phenotype is the result of genetics and the environment.
Reference please. Allan Keith
Allan, we do not know what determines form. That means we do not know if the phenotype is the result of genetics and the environment. ET
From my brief read of the article, it appears to be caused by epigenetics (methylation). How is this different than what we have known for over half a century? That phenotype is the result of genetics and environment? Allan Keith

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