An individual’s genome or whole genetic material may not be the right “book” of their life and inheritance
The genome or all of an individual’s genetic material may not be the right “book” of their life history and inheritance, write these University of Maryland scientists who reduce the DNA to a messy list of ingredients. Rather, the data that determines inheritance is stored outside the genome, in the molecular interactions that regulate cellular DNA, the researchers say in the Journal of the Royal Society Interface.
The common view of inheritance is that all information passed from one generation to the next is stored in the organism’s DNA. But this is not the opinion of Antony Jose, associate professor of cell biology and molecular genetics at the University of Maryland for whom DNA is only the list of ingredients, not all of the instructions. which determine and keep alive a living organism. These famous instructions would rather be stored in the molecules which regulate the DNA of a cell as in other systems.
A new framework for heredity?
After 20 years of genetic and epigenetic research, the researcher describes DNA as a disorderly list of ingredients used differently by different cells at different times.
One or two examples:
the eye color gene exists in every cell in the body, but the process that produces the eye color protein only occurs at a specific stage of development and only in the cells that make up the pigmented part of the eyes. Thus, eye color is not information stored in DNA;
similarly, DNA does not allow scientists to predict the complex shape of an organ such as an eye. Thus, the fundamental aspects of anatomy are dictated by instructions “located” outside of DNA;
According to the scientist, it is the whole process of development, from the fertilized egg to the complex organism, which must be considered an integral part of heredity. Heredity is therefore no longer a base of fixed instructions but a whole complex and networked information system in which all the regulatory molecules which help the cell to function take part.
Heredity should rather be approached as a molecular dynamic: this approach provides an answer to many questions that remain unanswered with current genome-centered biology. “Understanding the transmission, storage and coding of biological information is an essential objective, not only for basic science but also for regenerative medicine”. It would therefore be these instructions not coded in DNA but inherent in the arrangement of molecules within cells and their interactions with each other that would be preserved and transmitted from one generation to another. “One aspect of heredity, namely that the arrangement of molecules is similar from one generation to another, is deeply underestimated and leads to all kinds of misunderstandings on the functioning of heredity”, summarizes thus the searcher.
Clinical and research implications:
in medicine, for example, research into the factors due to which hereditary diseases affect people differently focuses on genetic, chemical or physical differences. This new view of inheritance suggests that researchers should look for non-genetic differences in the cells of individuals with hereditary diseases, such as the arrangement of molecules and their interactions. A new paradigm that will require new methods and new research tools.
This new vision also helps to explain the recently revealed weight of epigenetics: organisms could evolve through these changes in the arrangement and interactions of molecules without changes in their DNA sequence.
Finally, this theory suggests the insufficiency of private DNA banks, therefore critical information stored in non-DNA molecules.
Very experimental work, but which opens up entirely new perspectives and reflections on evolution, suggests significant paradigm shifts in genetics and epigenetics.
Source: Journal of the Royal Society Interface April 22, 2020 A Framework for Parsing Heritable Information