Science
Sizzle
The science of sunburn By Caitrin Crudden Illustration by Matheus Dyczynski
As the sunlight fades from our Swedish world very quickly, we take a look at the nature of our relationship with the sun, and the potential danger our Scandinavian sun worshipping habits may hold. As I sit here, a few weeks after my south-east Asian vacation, peeling skin like a strange snake lady, it’s an apt time to ponder the frustrating trauma of sun induced skin damage. As a native of Ireland, I am blessed with skin so pale that it can only be classed as white in the summer months, as throughout the winter I’m a definite blue, and as a result seem to burn no matter how much I bathe in sun cream. Let’s take a moment to follow the sun light that we of Swedish residence spend the summer chasing, as winter ragged darkness has turned us into hypnotic moths. So you are on the beach, near or far, and you present your skin in worship to the great big ball of fire in the sky to feel its soothing warmth. Let’s, for a moment, hypothetically climb aboard a sunray and follow it earthwards. The ray of interest is ultraviolet (UV) light, a light that is of higher energy than that which we can see with our eyes. The protective ozone layer filters out the highest energy and most dangerous UV-C radiation, but it lets through some UV-A and UV-B, which reaches our poised beached bodies. As you feel the warmth, your skin is being bombarded with UV rays. If you 18
are not of a naturally dark pigmentation, this UV is detected by pigment producing cells in your skin called melanocytes. These cells rush to protect you against potential damage and start producing and redistributing a dark pigment called melanin. You can think of them like putting up lots of tiny brown umbrellas to protect the deeper down and more important cells (more on that later), and over time a tan will develop.
When the UV-B ray hits the DNA, connections between nucleotides form that are not supposed to be there At some point in time, an ancestor of mine acquired a random mutation in a melanin producing gene which meant that they were unable to produce this protective pigment any more. Normally, if a mutation arises which is particularly detrimental to an individual’s heath, it will not spread, because that carrier will be less likely to produce offspring, due to ill health or early death. In the case of melanin non-production, this is likely to
have stuck around because this ancestor had already migrated to an area of the world where direct sun exposure was not common enough to pose a high risk (logical, if you have ever experienced the 300 odd days of rain in Ireland per year). And hence, those with a milk-bottle like complexion like my own are more susceptible to sun induced skin damage, because we cannot produce that protective pigment melanin. Or to wrap up my metaphor, we do not have any little brown umbrellas, and are therefore much more likely to get wet. It is important to note here, whether the melanin protective mechanism is present or not, (darker pigments are still not completely protective, UV-B can still sneak through in some parts), dangerous UV-B rays reach the epidermis, the outermost layer of the skin. Even if you do have the ability to tan, unfortunately this process takes quite a period of time, and therefore a lot of damage can be done before your protective layer kicks in. In the meantime, UV rays penetrate the cell layers and enter individual cells, whizz past their cram packed contents and hit that central bag, the cell nucleus. The nucleus holds the genetic blueprint, the DNA, which carriers your genetic code in four