- Thread starter
- #81
Sigh. Well, it looks like the peanut gallery here needs an introductory course in epigenetics.
Let's start with "traits that are transmitted without DNA".
Then we move on to DNA methylation.
From there, we go to histone methylation.
Which falls into the general category of "post translational modification".
Here's how it works
A histone is a protein that binds to the DNA and determines how much of a gene is expressed.
Mutations in histones therefore alter genetic expression.
Without changing the DNA sequence.
Histones also help methylate the DNA, which is another thing that doesn't change the sequence.
Histones that happen to be present in gametes and germ cells can therefore affect development, altering both the number and sequence of proteins that are being transcribed. All without changing the DNA.
However if they happen to bind to DNA repair sequences, they CAN change the DNA - which isn't a mutation, it happens "after" a mutation.
One of the interesting cases is a histone that binds to the gene that codes for itself.
Another interesting case is a histone that turns off other histones.
Histones are involved in things like immune memory. And possibly synaptic memory too. There is cytosolic histone outside of the nucleus, and it's released in vesicles (exosomes, which may contain neurotransmitter).
The bottom line is DNA doesn't exist in isolation. It's always associated with proteins. So is RNA, and that's especially important in neurons, where RNP's travel into the synapses (like at dendritic spines, where they regulate AMPA receptors).
pubmed.ncbi.nlm.nih.gov
en.wikipedia.org
en.wikipedia.org
www.cuimc.columbia.edu
www.gesundheitsindustrie-bw.de
en.wikipedia.org
Let's start with "traits that are transmitted without DNA".
Then we move on to DNA methylation.
From there, we go to histone methylation.
Which falls into the general category of "post translational modification".
Here's how it works
A histone is a protein that binds to the DNA and determines how much of a gene is expressed.
Mutations in histones therefore alter genetic expression.
Without changing the DNA sequence.
Histones also help methylate the DNA, which is another thing that doesn't change the sequence.
Histones that happen to be present in gametes and germ cells can therefore affect development, altering both the number and sequence of proteins that are being transcribed. All without changing the DNA.
However if they happen to bind to DNA repair sequences, they CAN change the DNA - which isn't a mutation, it happens "after" a mutation.
One of the interesting cases is a histone that binds to the gene that codes for itself.
Another interesting case is a histone that turns off other histones.
Histones are involved in things like immune memory. And possibly synaptic memory too. There is cytosolic histone outside of the nucleus, and it's released in vesicles (exosomes, which may contain neurotransmitter).
The bottom line is DNA doesn't exist in isolation. It's always associated with proteins. So is RNA, and that's especially important in neurons, where RNP's travel into the synapses (like at dendritic spines, where they regulate AMPA receptors).
Extra-nuclear histones: origin, significance and perspectives - PubMed
Histones are classically known to organize the eukaryotic DNA into chromatin. They are one of the key players in regulating transcriptionally permissive and non-permissive states of the chromatin. Nevertheless, their context-dependent appearance within the cytoplasm and systemic circulation has...
pubmed.ncbi.nlm.nih.gov
Histone methylation - Wikipedia
Messenger RNP - Wikipedia
Acquired Traits Can Be Inherited via Small RNAs
Columbia University Medical Center (CUMC) researchers have found the first direct evidence that an acquired trait can be inherited without any DNA involvement.
www.cuimc.columbia.edu
Epigenetics – heritable traits without changing the DNA sequence
Epigenetics, i.e. the inheritance of traits that does not involve a change in the DNA sequence, was once a controversial subject that has since become a central focus of biological research.
www.gesundheitsindustrie-bw.de
