Pour dévier, une découverte récente rendant un peu plus clair de l'inexpliqué de la vie et de notre existence, gros ou maigre, etc.. :
Un code caché dans l'ADN de nos gènes évolue beaucoup plus vite que nos gènes, une forme d'épigénétique avec son code à éclaircir (actuellement observé, mais inexpliqué comment il fonctionne !)
Pour les souris et même les hommes, la tendance à l'obésité après des conditions difficiles (famine), se passe de génération en génération sans modification du code génétique !!
Cet article observe la nécessité de ce code caché, mais il reste à découvrir tout ce qui l'explique et permet de comprendre.
C'est pourquoi les OGM, de fait modifications rudimentaires des gènes, qui, de fait, restent quasiment incompris, avec ce code épigénétique à découvrir, sont un danger de conséquences imprévisibles sur la vie que nous n'avons pas décodée !!!
Are genes our destiny? 'Hidden' code in DNA evolves more rapidly than genetic code, scientists discover
http://www.physorg.com/news/2011-09-gen ... e-dna.html
et l'info du labo :
http://www.salk.edu/news/pressrelease_d ... ess_id=516
http://www.salk.edu/news/pressrelease_d ... ess_id=507
In fact, many of the major discoveries that led to these conclusions were based upon studies in plants. There are traits such as flower shape and fruit pigmentation in some plants that are under the control of this epigenetic code. Such traits, which defy the predictions of classical Mendelian genetics, are also found in mammals.
In some strains of mice, for instance, a tendency for obesity can pass from generation to generation, but no difference between the genetic code of fat mice and thin mice explains this weight difference.
The study, published today in the journal Science, provides the first evidence that an organism's "epigenetic" code - an extra layer of biochemical instructions in DNA - can evolve more quickly than the genetic code and can strongly influence biological traits.
Ecker said the results of the study provide some of the first evidence that the epigenetic code can be rewritten quickly and to dramatic effect. "This means that genes are not destiny," he said. "If we are anything like these plants, our epigenome may also undergo relatively rapid spontaneous change that could have a powerful influence on our biological traits."
Now that they have shown the extent to which spontaneous epigenetic mutations occur, the Salk researchers plan to unravel the biochemical mechanisms that allow these changes to arise and get passed from one generation to the next.
They also hope to explore how different environmental conditions, such as differences in temperature, might drive epigenetic change in the plants, or, conversely, whether epigenetic traits provide the plants with more flexibility in coping with environmental change.
"We think these epigenetic events might silence genes when they aren't needed, then turned them back on when external conditions warrant," Ecker said. "We won't know how important these epimutations are until we measure the effect on plant traits, and we're just now to the point where we can do these experiments. It's very exciting."
