Fishing in the gene pool for Vikings: A review

We are sea-rovers, genetically. That is to say, you’re probably a Viking – but that’s not very exciting because so are most Europeans. If you’re from another part of the world and reading this, I imagine you aren’t so fussed about Viking heritage.

Vikings were fishers and merchants forced onto the open seas to escape their over-populated land in search of a livelihood. Vikings are romanticised and mythologised and made into TV shows and video games (both new and old). People pay good money to find out if they were born from Viking stock. Eddie Izzard subjected himself to a BBC programme about his genetic ancestry, discovering that he, like many others, descends partly from Vikings. So the essence of the question is not whether you are a Viking, but how much of a Viking you are.

The degree of one’s Viking-ness was the subject of a talk last Friday evening at the British Museum. Mark Jobling, a professor of genetics at the University of Leicester, held the podium to tell us what it means when we talk about the genes of the sea-rovers.

(Incidentally, the British Museum’s Great Court – two acres of brilliant light under a latticed glass sky – was designed by Norman Foster, whose younger brother – Steve – is a boxer known as “The Viking.”)

Mark Jobling, who in real life is beardier and more suave than his homepage photo suggests, is a man with many facts lurking around the corners of his mind, ready to spring into action on a moment’s notice. At the end of his talk, Jobling fielded a question about why more scientists don’t study Spanish genetics. His reply casually dropped facts about the Moorish invasion of the Iberian Peninsula in AD711 as if expecting the audience to think, “Oh yes, of course, that old skirmish.” I wish my brain housed an intimidating smorgasbord of facts.

But that’s the end and I should start at the beginning. Or maybe a little further back. In 2012, Jobling told the journal Nature: “If men have a Y chromosome that is more common in Scandinavia than England, they’re convinced they’re a Viking.”

Y chromosomes are sprigs of DNA that tell embryos to develop into males (among other things). They’re passed only from father to son. Together with mitochondrial DNA – passed only from a mother to her children – these stretches of genetics form around two percent of your genome.

These inheritance patterns make Y chromosomes and mitochondrial DNA (mtDNA, if you want to sound cool in a scientific conversation) interesting to study. The idea is to find similarities between your copies and other clusters of Y chromosomes or mtDNA around the world.

Jobling’s research looks at genetics alongside another inherited unit: surnames. In Scandinavia as well as in the UK, surnames tend to be passed from fathers to sprogs. Traces of Viking live on in the surnames of some English people – names containing a ‘thor’ (Thorpe, for example) or a ‘by’ (Norwegian for ‘town’, as seen in the name Willoughby). Vikings also invaded Ireland, founding the city of Dublin, among others, as a Danish kingdom. A number of people there carry Viking surnames – MacAuliffe, for example, meaning ‘Son of Olaf’ – although Jobling’s work hasn’t found much in the way of Viking DNA in Ireland.

Jobling told us it’s harder to untangle the exact genetic roots of people who might be descended from Danish Vikings. They may have migrated too long ago (apparently this kind of study struggles to look beyond 700 years in the past). The genetic signal from Danish Vikings also mixes with Frisians and Jutes to confuse matters.

There is not likely to be a clear signal from your ancestors within your genome. The DNA in your body is muddled up the way it is because your ancestors moved around and – avert your eyes – had sex.

Although his talk was fundamentally about the genetics of ancestry, Jobling couched everything in its history, providing examples, stories and context. As well as making statistical inferences about the past, Jobling also creates computer simulations in an attempt to realise what he called the “unknowability of the past” – to compute the most likely version of events.

Genomes, Jobling said, are like computer programs. Computer code is just gobbledegook – especially if you just look at the on/off electric sparks of binary. You can’t tell from a stream of 1s and 0s whether you’re looking at Excel or the Mail Online’s Sidebar of Shame. For that, you need to let the computer translate. Similarly with DNA: tiny machines in your cells translate your genome into proteins and other chemicals, which in turn allow your body to churn its way through daily life.

Fossils, long bereft of life, sometimes still contain DNA. Over the past few decades, researchers have developed techniques to extract and examine this ancient DNA. Reading the genes of these ancient people, one can perhaps learn their eye colour and their risks of developing heart disease. We could possibly sketch a picture of our ancestors’ ancestry and compare their genes to those of people alive today.

But what if these long-dead people didn’t reproduce, didn’t leave any descendants – were evolutionary and genealogical dead-ends? In hindsight, this is an obvious point I’d never considered before and one that might further befuddle genetic ancestry.

The stage in this lecture theatre underneath the British Museum’s Great Court is backed by a glossy red surface, reflecting the audience – distorted faces of the present thinking about the past.

A final, thoughtful point raised by Jobling: in a world of sperm and egg donations and perhaps mtDNA donations leading to three-person IVF, how might current and future generations understand themselves through genetics? This evening made it clear we can only do so in a wider context, enlightened by other histories.