Everything what we have in our genome is stochastic gift from evolution. Thus everyone knows that childbirth is a genetic lottery. Random combination of mothers and fathers chromosomes leads to new unique baby’s genome. And normally we can nothing to do with our DNA…except genome editing. But what if we responsible for our future children genes? What if our lifestyle and environment influence our genomes?
Transgenerational epigenetic inheritance is an inheritance process independent of the classical Mendelian inheritance. It requires genetic information changes of a germ cell (sperm or egg) to transmit the environmentally induced organism characteristics between generations.
Weissman’s barrier suggests that only the germline can transmit genetic information between generations. Epigenetic inheritance is parent–child transmittance of inherited information without altering primary DNA sequence. Parents change their germ line cells genomes using epigenetic mechanisms: DNA methylation and histone modification. That modifications code the information of transcription levels- how many copies of each protein or RNA cell have to produce.
Methyl groups are added to the DNA molecule without nucleotide code replacement during DNA methylation. For example, gene repression is associated with methylation of gene regulation element promoter.
DNA is wrapped around special proteins- histones in cell nuclei. Imagine DNA as thread spools around the reel. Histone modification means additing or removing of extra marks from histone. Several label types – methyl, acetyl, etc. added to protein’s aminoacids have different meanings. All this modifications we can interpret as histone code.
Environmental and dietary factors can affect DNA methylation and histone modification intergenerationally in plants and animals.
For example, in rats alcohol exposed male and female offspring showed a significant deficit in proopiomelanocortin (POMC).
POMC is cleaved to give rise to multiple peptide hormones. One of them beta endorphin is responsible for producing euphoria and pain relief.
Another one, Alpha melanocyte stimulating hormone has important roles in the regulation of appetite and sexual behavior. Scientists described epigenetic modifications of Pomc gene that transmit through generation via male germline and may be critically involved in alcoholism-inherited diseases. Researchers found both ways of epigenetic inheritance mechanisms in this rat-alcohol model: increased methylation status of the Pomc promoter region and altered level of histone modifying proteins in POMC neurons.
Evidence of transgenerational epigenetic inheritance in plant and animal models suggests that it may be a ubiquitous phenomenon in eukaryotic organisms and could plausibly occur in eukaryotes including humans. Interestedly, patients with a family history of alcoholism has lower POMC containing neuron activity.
So maybe we need to change our minds and stop considering genetic inheritance as fate. Bad habits are little foxes that spoil the grapes of healthy genome. It is blind irresponsibility that is an annihilating blight which destroys root and vine.
Do you want more? My popsci lecture about epigenetic inheritance will be held on 18 February at the http://worldmodel.co/ meeting.
Follow the link for registration: https://www.facebook.com/events/1657705047864557/?ti=icl