Nurture begins in the womb

25 Aug
Epigenetics is the study of the chemical reactions that govern which genes get turned on or off. Wikipedia image credited to the National Institutes of Health (NIH).

Am I hungry? Have I just gotten sloshed? Am I in outer space?

All of these factors affect how I am feeling, and less obviously, how my genes are functioning.

If I am a pregnant lady, factors like these become critical because they impact the activation and silencing of genes that coordinate the delicate orchestration of my baby’s development.

Remember, genes are the same in all of our cells, but our cells and body parts look and behave differently because certain genes within them are switched on or off. And in order for the cells of a developing embryo to emerge is a person, genes need to be switched on and off at just the right moment.

What’s controlling these switches? It’s not the genes themselves. Epigenetic signals –(click this for great videos and articles on epigenetics from the University of Utah’s Genetic Science Learning Center) –are the conductors that cue genes in and out at just the right time. They change in function of what we eat, smoke, breathe and drink.

In our own bodies right now, epigenetic “conductors” are turning genes on and off within our cells. The “music” is somewhat improvised, because the conductors are reading and catering to an “audience” of chemical, cellular and magnetic wave signals in their environment. And as experienced showmen, the conductors also call on memories of past audiences to guide their work.

That is to say, our cells have memories. Epigenetic characteristics accumulate as we get older. They may pass from parent cells to daughter cells, and sometimes they are even passed from parents to kids. Thus the effects of a major stressor like a famine can actually have consequences across generations. Women may be exposed at some time in their lives to environmental toxins that get stored in their bodies and never come out until they have children who inherit a portion of them.

Just after fertilization, the first, undifferentiated cell that will become an embryo sits in the fallopian tube ready to read and react to its environment.

During the first stages of differentiation, its “hard drive,” or epigenetic package, gets mostly wiped.

During the first dozen cell divisions, the markers of cell identity inherited from parents are stripped down to the basic bare bones to make way for a new being to arise in its own unique pattern.

And once the slate is mostly clean, the cells begin to react to the chemicals around them. Those signals come in and stimulate the establishment of a new epigenetic matrix.

Various epigenetic signals can impact development.

As drivers we often find ourselves blocked or diverted by orange traffic cones, and these cones are owned and set out by various characters in our society. Energy guys, interstate guys, phone guys, and emergency guys all got ’em on their trucks. Similarly, epigenetic signals from many different sources affect the genome. They come from in and outside of our bodies, from chemical signals excreted by our cells to things that we eat, drink, or breathe.

Chemicals that mom ingests stimulate epigenetic mechanisms to lay down patterns that affect gene expression. And, because epigenetic patterns are cellular memory, these can have immediate or long-term effects. Some epigenetic patterns are reversible, and some are not.

When the cells of the embryo aren’t reading their “conductors” correctly, then you may have a tuba blare in the middle of a soft strain from a violin quintet. Typically, a feedback will shut that tuba down, but in extreme cases, the tubas can cause minor to fatal developmental problems. If a pregnant mom takes the wrong drugs, she can stir up a marching band of tubas that shut down or overwhelm the signals that turn genes on and off.

In light of the role of epigenetic factors, the nature vs. nurture debate can’t easily fly. Nature and nurture are inseparable. From pregnancy day 1, they’re physiologically intertwined.


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