Give your baby's genes a boost.

A full 50 years before Darwin published his theory of natural selection, Lamarck theorized that an organism would pass on environmental adaptations to its offspring. If you cut the tails off three or four generations of mice, you’d soon see a few tail-less babies.

Darwin, on the other hand, felt that our genes were hardwired and inherited unchanged from our parents. And then passed unchanged to our kids. Life experiences did not affect future generations. You could cut off as many mouse tails as you’d like, but would never see tail-less mice in future litters.

This assumption of a hard-wired inheritance ruled the science of genetics for over a hundred years. However, the last few decades have seen a shift in this absolutist view. Why are two identical twins (exactly the same genetic makeup or genotype) often slightly different in appearance (phenotype)?

The study of differences in genetic expression, that is how identical genes are turned on, off, or are somewhere in between, is called epigenetics. A specific cell protein, miRNA, seems to be the switch that impacts how our hardwired genetic code is interpreted.  And lifestyle has been shown to directly impact cell miRNA levels.

A recently published study on brain physiology shows the link between the increase in miRNA levels in the brains of regularly exercised mice and a corresponding increase in brain nerve cell connections.  This was not unexpected as we knew from prior investigations that the level of our exercise directly correlates with brain health.

Surprisingly the researchers also found the same increase in miRNA levels in the sperm of the exercising group as well as improved brain development in their offspring. (It is fair to assume that the same miRNA changes occurred in the eggs of exercising female mice, but it was a lot easier for the experimenters to collect sperm from male mice than harvest eggs from the females).

These elevated miRNA changes in the babies soon returned to normal levels if the baby mice did not exercise as they grew. And the grandkids of the original study mice returned to a normal pattern of mouse brain development as would be expected with a similar, unaltered genetic makeup.

Even though this study focused on exercise, we know that other daily activities and exposures can impact miRNA levels, and that miRNA levels can in turn impact other aspects of genetic expression including, for example, cancer development.

It has been speculated that exposure to toxins in our environment (pesticides for example), medications and illicit drug use, and even diet can impact on our miRNA.

Thus, our development (and, in turn, our kids) is not just limited to the genes we inherit from our parents (and their parents).

This means that you can have direct, but limited, control to maximize the benefits of your genes and in turn your genetic contribution to your kids. But for that extra bit of benefit to be passed on to another generation, your kids would also have to adopt a similar “healthy” lifestyle.

And while you are helping give your kids a healthy boost to their genes, you will benefit from this healthy lifestyle. The exercising mice all benefited from a more connected network of nerve cells in their brains which it can be speculated what translates into a decreased tendency to develop Alzheimer’s. And we also have that suspected link between miRNA levels and cancer development.

So, when you are vacillating on that decision to buy the slightly more expensive pesticide free produce at the local QFC, or get out for that all too easy to skip afternoon walk, remember that the decision you make will impact a lot more people than just you.

https://www.nytimes.com/2018/05/09/well/move/do-fathers-who-exercise-have-smarter-babies.html

https://www.cell.com/cell-reports/fulltext/S2211-1247(18)30404-2

https://www.ncbi.nlm.nih.gov/pubmed/17413852