Are the fantasies of superheroes so far-fetched, or might it be possible to change our bodies to acquire superhuman abilities? Epigenetics, one of the most recent and important discoveries in the science of heredity since the gene, might hold the answer.
Biology students have traditionally been taught: “1. The genome contains all the instructions necessary to make up an organism; and 2. Genes are passed on unchanged from parent to child, and to subsequent generations: any genetic changes brought about by lifestyle cannot be inherited.” These ideas now appear to be outdated (although it might be worth remembering them for your biology exams).
It turns out that there is another set of instructions, known as the ‘epigenome’. These instructions are additional to the genome: interacting with and modulating our DNA. By switching certain genes on or off, the epigenome determines which genes get expressed into traits. But this is not the end of the story. Epigenetics happen as a response to a signal from our environment, meaning that changes brought about by nurture can indeed be inherited. In other words, once made, epigenetic changes can be very long-lived, lasting greater than one or two life-times.
So the word ‘epigenetics’ means both ‘the development of an organism through the regulation of how genes are expressed’ and also, ‘forms of inheritance of these modifications of DNA sequences’.
But, what exactly is the power of epigenetics? One of the most clear-cut examples of the influence of the epigenome can be seen in identical twins. Since they come from a single embryo, they share the same genome, and, being twins, they shared a very similar environment in the womb. But as the twins get older, their social interactions, diets, differences in physical activities, and exposure to toxins such as cigarettes, differ. These environmental factors create different needs and signals in their bodies; the epigenome responds by activating and silencing different genes in order to cope with the varying demands. Since the environment of the twins is different, their epigenome responds differently. The genomes of the twins are unaffected, but their epigenomes change, leading to different patterns of genes.
The exciting discovery of epigenetics has led some to question whether we can use this newfound knowledge to enhance our physical condition. And like Peter Parker after being bitten by a genetically modified spider to become Spiderman, we won’t have to go through the trouble of replacing our whole genome; we just need to modify it. So now we know that the correct question isn’t: “what gene can I delete or acquire in order to become stronger?” Instead, we should ask: “can I epigenetically regulate the genes I already have to make my muscles grow larger and stronger?”
If it’s endurance you want to improve, the genes responsible for generating red blood cells could be tweaked so that abnormally high levels are created and your muscles are supplied with oxygen faster than normal. You’d be able to do physical activities for hours, while experiencing less fatigue. If you want to acquire Sherlock Holmes’ abilities of deduction, it might be a little trickier to tackle, but increasing the neuron development in our brains would help.
Exactly how to upscale or downscale the expression of genes is currently not well understood, and is under intensive investigation, so superhero-like abilities may not be possible for some time. However, epigenetics will clearly have many important applications in the future of medicine.
IMAGE: ethermoon, flickr