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[Reblog] Epigenetics – how the environment influences our genes

Epigenetics – how the environment influences our genes › Lindau Blog.

“..today we must assume that if our generation is suffering hardship, violence or the like, not only will we struggle to forget these difficult periods ourselves but our genes too will remember them, carrying traces to be passed on to the next generation or even several generations.”

From the 8 May 2015 post at Scilogs

The science behind a rapid paradigm shift

When the first human genome was decoded, popular thinking went: “If we know the genes, we know the person.” Today, barely 15 years later, science is in the middle of an exciting new area of research, which is entertaining interested members of the public with exciting, if not always serious, headlines. The field alleges that traumatic experiences can be passed down through the generations and even significantly affect the lives of grandchildren. As it turns out, the reality is that genes not only control, but are also controlled. And that is what epigenetics is all about – how are genes controlled and what factors can influence them?

Epigenetics refers to the meta-level of genetic regulation. Under the influence of external factors, epigenetic mechanisms regulate which genes are turned on and off. This helps our fixed genetic material to be more flexible. At the biochemical micro level, epigenetic regulators are responsible for how closely packed individual genomic regions are and therefore how accessible or not they are. This works by small adhered or detached chemical groups. The resulting marking of the genome is read by specialised enzymes that then cause the switching on or off of the genes.

English: Structure of a nucleosome with histones from the fruit fly, Wikimedia Commons (Sponk)

As reasonable as this appears, one consequence is that we will have to say goodbye to a long-established dogma: the idea that genes are immutable in the creation of a living being. And, looking back through the history of science: was Lamarck right, after all? The 19th-century French biologist had claimed that organisms acquired traits to pass on to future generations . It is precisely this mechanism that epigeneticists are on the trail of today. Laboratory experiments with mice have demonstrated that a particular, targeted encoding of individual genes results in the changes being passed on to the offspring. Epigenetic changes, however, are so-called soft changes, as they can be undone. And that is medicine’s great hope – to be able to intervene in the control mechanism from the outside in order to be able to work against, for example, senile dementia.

PET scans showing the differances between a normal older adult's brain and the brain of an older adult afflicted with Alzheimer's disease, Wikimedia Commons (Health and Human Services Department, National Institutes of Health, National Institute on Aging)

At this point, the level of possible tension around this new field of research becomes clear. On the one hand, the idea that our human condition can be so strongly “manipulated” by environmental influences can be very disturbing. And rightly so. Previously, we may have had the upbeat expectation that although we are experiencing suffering, the next generation will have it better. However, today we must assume that if our generation is suffering hardship, violence or the like, not only will we struggle to forget these difficult periods ourselves but our genes too will remember them, carrying traces to be passed on to the next generation or even several generations.

study often mentioned in this context is based on the analysis of data collected in the Netherlands over the years of hunger in 1944-45, during which the population there suffered particularly difficult conditions. The children born at this time were not only smaller, but, as adults, had an increased risk of obesity, cardiovascular problems and neuropsychiatric disorders. In turn, their offspring were again smaller than average – despite food being in ready supply and living conditions having greatly improved.

 

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May 18, 2015 - Posted by | Medical and Health Research News | , , ,

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