As if there were not enough ground shaking discoveries to go around in the field of brain research, a huge paradigm shift is underway not only in brain research, but in all of biology. The breakthrough is called epigenetics. Basically, epigenetics turns our prior smug assurances about evolution and heritability upside down. We made fun of the Frenchman Lamarck for his notion of characteristics acquired during an animals lifetime being passed to its offspring. Epigenetics as a field has discovered that much of the formerly considered “Junk DNA” actually is responsible for genetic manipulation due to factors that we experience during our lifetimes.
The genetic structure of “DNA” as we know it does not change during this process. However, the “switches” that turn DNA on and off can be changed during a lifetime by certain events. There are over 2,000 proteins thus far that can be manipulated by the process known as acetylation. The modification of histones also comes into play. These changes are within our genetics and can be passed down to our descendants.
The field of epigenetics was relaunched in 1942 by Waddington, but it was not until a more recent study in Sweden that the full ramifications became evident. In a town known for its periodic starvation in the early twentieth century, researchers found that the stress of starvation generated heritable changes in the individual who had experienced starvation versus someone who had not. These changes in physiology such as body fat ratio, pre-disposition anxiety and depression were found to be directly related to the life experiences of the Swedes being studied. Many other examples have come forth over the past several years.
In terms of brain injury research, there are significant ramifications coming out of epigenetics. In a study entitled “Long-Term Epigenetic Modification After Mild Traumatic Brain Injury” (Darwinsh H, 2010) showed that mice with induced MTBI showed bio-markers for epigenetic changes 35 days after injury. Because similar studies involving neuro-chemical and axon changes after trauma in the human brain have shown, contrary to our expectation, that the changes are chronic and ongoing for up to seventeen years, it is likely that these epigenetic changes are going to be found to be chronic. The likelihood is that some of the adverse consequences associated with TBI are going to be transmittable to the next generations. These would include:
• Susceptibility to depression
• Susceptibility to anxiety.
• Perhaps decreased resistance to alzheimer’s and parksinson’s.
• Maladaption to stress and cortisol.
There should be a lot of work coming out on this in the next six months to one year. As if TBI victims didn’t have enough to worry about regarding recent research! The idea of trans generational tort damages, either suffering them as a plaintiff or paying for them as an insurance company, is for another day. Indeed.