An investigation into more than 500 children shows that upbringing can have dramatic effects on human health.
DNA is the genetic material that makes us who we are, determining our physical characteristics and even helping to shape our personality. There are many ailments that have a strong hereditary component—Alzheimer’s, Huntington’s Disease, cancers and diabetes among others—and the risk of suffering them is passed down from our parents through our DNA.
But we’re finding out that our DNA isn’t always set in stone. Now, a team of researchers from Northwestern University led by anthropology professor Thom McDade have shown that DNA can also be modified by your environment during childhood. What’s more, the authors conclude in the journal Proceedings of the National Academy of Sciences, those modifications can affect how or when you develop certain illnesses during adulthood.
Their investigation followed more than 500 children in the Philippines and found that certain childhood situations can create modifications in genes associated with inflammation, which affects how prone we are to suffer from certain illnesses. Specifically, these factors included socioeconomic status, the prolonged absence of a parent, the duration of breastfeeding, birth during the dry season, and exposure to microbes in infancy.
But what exactly do the findings mean?
DNA is, in essence, a really long text made up of a 4-letter alphabet that our cells use as an instruction manual for making proteins. The order in which the letters are arranged (the DNA sequence) defines the genes that a person has, which remain the same throughout that person’s body. Despite that, only some genes (or sentences in the DNA text) are necessary for each cell type to function.
If genes are sentences within the DNA text, epigenetic marks are like differently colored highlighters that indicate which genes a cell should express (importantly, they do not change the sequence of the DNA). The most important of these marks is methylation, or the addition of a methyl group to the DNA molecule, which promotes or inhibits the expression of certain proteins depending on which gene it is on and where on the gene it is located.
“We could have genes in our bodies that might lead to some bad outcomes or adverse health outcomes, but if those genes are silent, if they’re turned off due to epigenetic processes, that can be a good thing,” explains McDade, principal author of the PNASstudy.
McDade adds that, for the most part, once a gene is methylated it remains permanently methylated. Although it is not quite clear how a person’s childhood environment causes the methylation of some genes, it is possible to investigate its effect.