Introduction to Epigenetics Part 1

SAY HELLO TO EPIGENETICS…..

Lets look a little deeper at how a mothers health and well-being can affect the development of their unborn child.

We have mentioned that children can be born with significant developmental and physical defects some of which are caused by modifiable behaviours of the mother.

By taking a look at one particular mechanism we can see on a molecular level how such behaviours can potentially result in lifelong consequences for the child, this mechanism is highly dependent on environmental factors like a mother’s behaviour and hormone levels. This area of research is on the frontier of science and is terribly exciting….

INTRODUCING EPIGENETICS……

Once upon a time we thought that our genome was an unchangeable blueprint for an individual. We thought you had certain variations of genes, and those genes gave rise to everything in your body. For instance they would lead to the growth of cells and stimulate the production of the many different types of cells like a liver or skin cell.  They would also determine what hair colour you’d have and whether or not you could roll your tongue into circle.^1,2

We thought that what cards you were dealt were the be all end all, HOWEVER, THAT IS NO LONGER THE CASE……

We now have clear evidence that there is a mechanism that can determine whether a gene will be expressed or not, in essence a mechanism that is capable of switching genes on or off. This mechanism termed epigenetics literally means ‘on top of the genome’ it is an added level of control over the expression of our genes^2,3….

Logically your next question may be, what causes this mechanism to turn a gene on or off?

The answer is that environmental factors, like nutritional status, living conditions, carcinogens and stress are just some factors that have been identified as key players in contributing to this event!^2,4-6

THIS IS INCREDIBLE! If you take a moment to think about what this means; we are saying that a person can alter the expression pattern of their genes on a molecular level which translates to changes on a macro platform. Meaning the blueprint genome in every one of your cells does not predetermine you biologically, what you do or in the case of a pregnant women what she does can change the expression of her offspring’s genes and hence alter the child’s physiology and therefore influence their health in later life!^2,5

This is a very rational, evolutionarily conserved survival mechanism. For example if the mother is starving because of famine, the fetus will not be receiving an adequate amount of nutrients. The message is interpreted that the environment the fetus will be born into is that of low food hence epigenetic mechanisms alter genes involved in the fetuses metabolism that will cause it to store as much energy as possible not just presently but also in later life!^7,8

Can you see more clearly how beneficial epigenetic modifications can be? In this case the fetus is prepared for an environment of low food, so when born, the child’s physiology is already programmed to function most efficiently for the environment it has entered!⁸

So why are we so excited about epigenetics?

This means that we can really begin to understand on a deeper level, why some people experience certain health outcomes. We can start to see the onset of disease from a much earlier timepoint THEN EVER BEFORE. Meaning we can really have a fighting chance at minimising or even PREVENTING the development of some conditions and maximise a child’s potential health outcomes in life!

We must remember however that there are two sides to every coin and in our next addition we will look at an example of how epigenetics can lead to deleterious development of a fetus…..

References

1.  Reik W, Dean W. DNA methylation and mammalian epigenetics. Electrophoresis. 2001 Aug;22(14):2838-43.

2.  Novakovic B, Saffery R. The ever growing complexity of placental epigenetics - role in adverse pregnancy outcomes and fetal programming. Placenta. 2012 Dec;33(12):959-70.

3.  Jones PA, Takai D. The role of DNA methylation in mammalian epigenetics. Science. 2001 Aug 10;293(5532):1068-70.

4.  Martinez JA, Cordero P, Campion J, Milagro FI. Interplay of early-life nutritional programming on obesity, inflammation and epigenetic outcomes. Proc Nutr Soc. 2012 May;71(2):276-83.

5.  Lucassen PJ, Naninck EF, van Goudoever JB, Fitzsimons C, Joels M, Korosi A. Perinatal programming of adult hippocampal structure and function; emerging roles of stress, nutrition and epigenetics. Trends Neurosci. 2013 Nov;36(11):621-31.

6.  Moonat S, Pandey SC. Stress, epigenetics, and alcoholism. Alcohol Res. 2012;34(4):495-505.

7.  Lumey LH, Stein AD, Kahn HS, van der Pal-de Bruin KM, Blauw GJ, Zybert PA, et al. Cohort profile: the Dutch Hunger Winter families study. Int J Epidemiol. 2007 Dec;36(6):1196-204.

8.  Heijmans BT, Tobi EW, Stein AD, Putter H, Blauw GJ, Susser ES, et al. Persistent epigenetic differences associated with prenatal exposure to famine in humans. Proc Natl Acad Sci U S A. 2008 Nov 4;105(44):17046-9.