Why Genes Aren't Your Destiny

Ahh, it's finally Saturday…the one day of the week to sleep a little longer, linger over my coffee, and spend a little extra time reading the stacks of things on my to read list.

Sure wish I knew the fine art of condensing information down into bite size pieces...I'm working on it...guess its a process just like everything else!

I’ve had the January 18, 2010 issue of Time Magazine sitting near the top of my pile for over a week and finally got to it this morning. I highly recommend finding a copy if you are at all interested in more information on how the choices we make today will have an impact on future generations. I’m continually amazed at how complex our mind, body & spirits are…fascinating information.

The article Titled “Why Genes Aren’t Destiny” by John Cloud, tells how the new field of epigenetics is showing how your environment and your choices can influence your genetic code-and that of your kids.

In the late 1980’s Dr. Lars Olov Bygren, a preventive-health specialist who is now at the prestigious Karolinska Insttitute in Stockholm, began to wonder what long term effects that feast and famine years might have had on children growing up in Norrbotten in the 19th century…they lived in a environment of literal feast or famine.

Around the time he started collecting the data, Bygren had become fascinated with research showing that conditions in the womb could affect your health not only when you are a fetus but well into adulthood. In 1986, for example, the Lancet published the first of two groundbreaking papers showing that if a pregnant woman ate poorly, her child would be at significantly higher than average risk for cardiovascular disease as an adult. Bygren wondered whether that effect could start even before pregnancy: Could parents’ experiences early in their lives somehow change the traits they passed to their offspring?

It was a heretical idea. After all, we have had a long standing deal with biology: whatever choices we make during our lives might ruin our short-term memory or make us fat or hasten death, but they won’t change our genes-our actual DNA.

What’s more, any such effects of nurture (environment) on a species’ nature (genes) were not supposed to happen so quickly...according to Charles Darwin. But Bygren and other scientists have now amassed historical evidence suggesting that powerful environmental conditions (near death from starvation, for instance) can somehow leave an imprint on the genetic material in eggs and sperm. These genetic imprints can short-circuit evolution and pass along new traits in a single generation.

For instance, Bygren’s research showed that in Overkalix, boys who enjoyed those rare overabundant winters-kids who went from normal eating to gluttony in a single season-produced sons and grandsons who lived shorter lives. To put it simply, the data suggested that a single winter of overeating as a youngster could initiate a biological chain of events that would lead one’s grandchildren to die decades earlier than their peers did. How could this be possible?

Meet the Epigenome
At its most basic, epigenetics is the study of changes in gene activity that do not involve alterations to the genetic code but still get passed down to at least one successive generation. These patterns of gene expression are governed by the cellular material-the epigenome-that sits on top of the genome, just outside it. It is these epigenetic “marks” that tell your genes to switch on or off, to speak loudly or whisper. It is through epigenetic marks that environmental factors like diet, stress, and prenatal nutrition can make an imprint on genes that are passed from one generation to the next.

There is evidence that lifestyle choices like smoking and eating too much can change the epigenetic marks atop your DNA in ways that cause the genes for obesity to express themselves too strongly and the genes for longevity to express themselves too weakly. We all know that you can shorten your own life if you smoke or overeat, but it’s becoming clear that those same bad behaviors can also predispose your kids-before they are even conceived-to disease and early death. WOW!

Pembrey, Bygren, and Golding-now all working together-used data to produce a more groundbreaking paper, the most compelling epigenetic study yet written. Published in 2006 in the European Journal of Human Genetics, it noted that of the 14,024 fathers in the study, 166 said they had started smoking before age 11-just as their bodies were preparing to enter puberty. Boys are genetically isolated before puberty because they cannot form sperm. (Girls by contrast, have their eggs from birth) That makes the period around puberty fertile ground for epigenetic changes: If the environment is going to imprint epigenetic marks on the genes in the Y chromosome, what better time to do it than when sperm is first starting for form?

When Pembry, Bygren and Golding looked at the sons of those 166 early smokers, it turned out that the boys had significantly higher body mass indexes than other boys by age 9. That means the sons of men who smoke in prepuberty will be at higher risk for obesity and other health problems well into adulthood. In other words, you can change your epigenetics even when you make a dumb decision at 10 years old. If you start smoking then, you may have made not only a medical mistake but a catastrophic genetic mistake.

All this explains why the scientific community is so nervously excited about epigenetics. In his forthcoming book isThe Genius in All of Us: Why Everything You’ve Been Told About Genetics, Talent and IQ is Wrong, science writer David Shenk says epigenetics is helping user in a “new paradigm” that “reveals how bankrupt the phrase ‘nature versus nurture really is.” He calls epigenetics “perhaps the most important discovery in the science of heredity since the gene.”
Looking forward to reading his book!