Monday, October 24, 2011

Longer life span can be inherited

By doing research on a special kind of worm, scientists have found that factors determining the life span of an organism can be passed down to future generations. This would seem like a genetical inheritable pattern, but it is not. The alterations that were studied focus on modifications to the structure that 'winds up' the DNA: chromatin. By modifying the 'spool' that is used to keep our DNA neatly packed, it was possible to elongate the life span of C. elegans, a model organism often used in the lab. Future generations of this worm appeared also to increase in life span, shedding light on mechanisms that could possibly let us live longer.

The study focused on so-called methylation of the DNA, which is a non-genetical modification of the blueprint that we use to create the elements for life. By methylating the DNA, it is possible to silence part of the genome, so it can not be translated into functional proteins anymore. When three enzymes that are responsible for methylating a specific part of the complex that holds our DNA, the chromatin, are shut off, the C. elegans worm lives longer.

It was found that the offspring of the modified worm live longer as well, even though the DNA itself, that is passed on to future generations, is not modified. It appears that the changes scientists made to the chromatin-altering enzymes are passed on in a non-genetical way. It was already known that modifications to the chromatin structure are inheritable, which means that these things basically function in a genetic way, even though they are not.

Humans possess the molecules that were turned off by the scientists. Therefore, stopping these methylating agents from doing their job could be a way to prolong our life span. Much more research is needed to confirm that hypothesis, of course. Humans are much more complex than C. elegans, a simple worm that consists of only a couple of hundred cells. It is likely that when the three enzymes that were part of this study are switched off in humans, the effect is not as profound, as we carry more life span-modifying agents in our body.

Studying changes in the chromatin structure, and other mechanisms that affect the function of our DNA is grouped into a single field of research, dubbed epigenetics. Editing by epigenetic enzymes is done constantly throughout life, and is important in specializing groups of cells: many parts of the genome are switched off by epigenetic editing, for example by methylation. This lets cells become what they need to be, without parts of the DNA that are required for other cell types in an active state.
The structure of DNA, eventually wound up in chromatin.
This study shares an interesting insight in how certain epigenetic factors can influence the length of an organism's life. Especially, the fact that it is inheritable makes it rather intriguing. Future research will most likely point out in what way we humans are influenced in our life span by our parents.

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