Gluckman - developmental plasticity

One of the principles of biology is that we are more plastic early in life. Clearly when we are only a bundle of a few cells, influences on those few cells magnifies through to bigger effects across those tissues as tissues develop from those individual cells. And many organs remain plastic only for a limited period in their life. So for instance, the brain is far less plastic by the time you are an adult, than when it is when you are a child. We can’t regenerate muscle cells beyond fetal life and so forth. And so the principles of developmental plasticity are fundamentally that the fetus is taking information from its mother, and making subtle changes in its development to try and optimize its success through life if it can.

It’s not so dramatic in humans, at least to our visible eye, as it is in some other species. The most obvious example is the honey bee. If you take the honey bee female larva; if the honey bee female larva is fed only on royal jelly, it will develop into a queen bee. If it’s fed on a mixture of royal jelly and other sources of food, it develops into a worker bee. Now a worker bee and a queen bee are quite different; one’s big, one’s small. They have different metabolism; they have different behaviours. They’ve got exactly the same genes. The only difference is the gene switches in early life.  The plasticity of the organism has been changed to develop into a queen or into a worker.

Now that’s a dramatic example, but what we think is happening in the fetus is, subtle changes are happening. The fetus and the embryo are taking information from the mother, and using that to make changes in the way its genes are turned on, how its organs develop, and how they function. Now of course it’s not a one to one relationship between what mother does and what the fetus sees, because in the middle there is another organ, called the placenta. And so there is many steps along the way; from mother living in the world, what she eats, the environment she sees, and what the fetus experiences which is largely buffered from the world out there by the placenta. But if the placenta is healthy, the only information the fetus is really seeing are the nutrient signals crossing the placenta, and some hormonal signals crossing the placenta. But if the placenta is not well, like in the case of preeclampsia, or in gestational diabetes, or malaria infection, then the placenta can is more likely to send a misleading information to the fetus, which means that it is more at risk.

So it’s a very complicated story, but again the bottom line is simple. That we want our mothers to be, our mothers when they’re pregnant, mothers before they get pregnant, the fathers before they get pregnant, to maintain healthy lifestyles, because it will make for better outcomes for the child in the next generation. And that’s what every parent wants.