The message has been repeated for 5 decades, everything or almost everything has DNA as its origin! IQ, intelligence, faith, crime, homosexuality and of course the majority of illnesses, including neurological and psychiatric syndromes. 50 or 80% of the origin of autism is genetic, the same goes for schizophrenia and even Alzheimer’s disease. This message is based on a rigid and non-modifiable or modular vision of DNA.
Yet in recent decades, it has increasingly become clear that the DNA sequence itself does not say much and is largely controlled by a series of mechanisms that block, enable or promote its expression. As a reminder, only 2% of our 2000 genes (about as many as the corn grain) encode these genes; the rest are considered “non-coding” and were until recently considered “junk genes”. It has since turned out that this majority of non-coding sequences have a fascinating history with transposable elements (E.T. that scientists have a sense of humor) originating from viruses. In 1948, Barbara McClintock showed that non-coding elements control the color of grains without modifying the DNA sequence. Since then, these “epigenetic” effects have been shown to manage important reactions and, moreover, can pass from generation to generation – are therefore “hereditary” without going through the coding sequence. Thus, stress or other event producing an epigenetic reaction during maternity can result in a syndrome (autism for example). Experimental data show, for example, that stress can be transmitted over several generations without any modification of the DNA but only through epigenesis, i.e. this ability to switch on a gene which will occur more easily in the descendant of this chain. On a more evolutionary level, these residues of viral origin have been integrated into our genome and allow us to better understand important leaps such as the exit by our fish ancestors from the waters to the terrestrial environment. These viral sequences are integrated for better and sometimes for worse (cancers), particularly in the control of the immune system. This system also operates in plants of course. The corn genome contains 80% of ETs and 68% of that of rice! Thus, the domestication of corn cultivated for 9000 years by Amerindian civilizations took place thanks to the intervention of an ET which activated a gene and facilitated the mutation of another gene. The same goes for the color of blood orange or white grape or the color of tomato varieties.
In summary, DNA is largely controlled by viral sequences imported during evolution, showing how things are not as simple as the genetic sequence. We will see in another summary how the methods used to deduce the “genetic” fraction of DNA are questionable and suffer from major handicaps.
https://pubmed.ncbi.nlm.nih.gov/22427337/
https://www.nature.com/articles/s41467-020-17874-2
https://pubmed.ncbi.nlm.nih.gov/15143274/
https://bionumbers.hms.harvard.edu/search.aspx?trm=rize+transposable+elements
