New research suggests that groups of genes talk to each other and pass the message down to next generations of cells. This is being described as “conditional memory” by Georg Fritz at University of Cologne and reported in MIT’s Technology Review’s Physics ArXiv blog.
Archives for September 2010
DNA over simplified or more complex?
In 2001 deciphering the human genome was thought to be a simple description of the parts list of a cell. Back then we thought simple translation of DNA would explain most of life and that each protein was the result of DNA being copied into RNA and then into amino acids and packaged as proteins. At that time I drew a picture attempting to describe that there would probably be much more complexity and variety. In my job as a nutritionist who sees many oncology patients it was clear to me that cancer cells were different by definition. I wondered why there wouldn’t be many other cells in our body in the process of deciding if a mutation or change in the DNA would remain or be edited out? Why wouldn’t our daily interactions with the outside (and inner) worlds affect this? Also, as we age wouldn’t these interactions impact and modify the text of our DNA like a copy editor(s)?
Learning the DNA complexity
Today we are learning that complexity is much more likely than simplicity in any of our explanations about DNA. First of all, did you know we have two types of DNA not just one? Ancient integration of bacteria is thought to be the reason why we have mitochondrial DNA not just nuclear DNA. These are single strands located in the power houses of each cell and found in huge quantities in liver and other highly metabolically active cells. With such a high level of turnover it makes sense that there would be a lot of modifications simply because of inaccurate or inefficient copying and repairing. Another factor is the addition of regulating “tags” such as methyl groups, called epigenomics. This is not well understood but apparently very important. Another reason that simple explanations no longer work is that it appears that rather than being randomly assorted, DNA strands in each chromosome show a wide variety of selection with some being determined by evolutionary pressure and whether of paternal or maternal origin. This is called imprinting.
Level of complexity
Some people find this level of complexity simply too much to ponder – rather like thinking about the vastness of our universe (part of a larger multiverse). Linear, logical thinking no longer describes the sophisticated biological systems that so elegantly explain life. A leading to B leading to C just doesn’t do it any more. But, we don’t need to understand astrophysics to appreciate a sunrise or sunset. I am in awe of how each time a discovery is made about genomics there is further complexity to impress us. The challenge from my perspective is how to drill down to what is meaningful and valuable for improving our health without being overwhelmed and switched off to the whole process just because it is so detailed.
Another layer of DNA
Another layer to add to this challenge is how each of us approaches discoveries from different personal histories and personalities. What I find fascinating may just be plain boring to someone else.
- I would love to hear from you – what do you think about it all?
- Are you uncomfortable or stimulated by this level of complexity?
- Do you see chaos or order or perhaps both at the same time in some kind of dynamic equilibrium?
The late Roslyn Alfin Slater, PhD, one of my mentors at UCLA, noted that adipose tissue is a relatively safe place to store toxins that aren’t readily removed (by liver or kidney detoxification processing). A recent examination of NHANES (National Health and Nutrition Examination Survey) showed a highly significant correlation between six environmental pollutants in serum and weight change. A second study found similar changes in 39 obese individuals subjected to a 15 week low calorie diet and looking at 26 organochlorine compounds in blood and body fat (subcutaneous). This underscores the importance of supporting liver and kidney detoxification processes by eating a high fiber, fruit and vegetable rich diet and avoiding environmental pollutants for health.
Int J Obes Relat Metab Disord. 2000 Oct;24(10):1272-8.
First we learn that it is less about what you do rather how little you sit down that affects your health and mortality. Sit less, move more! (Patel, et al. Am J Epidemiol 2010:172(4)419-429)
Another study (with mice not humans) indicates that voluntary exercise is highly heritable meaning wanting to sit more may be something you are programmed to do (Garland, et al. Proc Roy Soc 2010, DOI 10. 1098/rspb2010,1584). Even if that is the case for humans (and many rodent behavior studies don’t pan out when applied to humans) then it simply means for those of us who find it hard to get to the gym we will still benefit if we get up, pace around and are just more active. “Use it or lose it” as Jack Lalanne would say – one of my heroes who is still amazingly active both physically and mentally in his 90’s. Go Jack!