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Family Fortunes: Adam Rutherford On How We Are All Related to Royalty

Posted on 14th September 2017 by Martha Greengrass
Having taken readers on a four-billion-year detective hunt for the origin of life in his book Creation, author, scientist and self-confessed geek, Adam Rutherford turns his attention to the stories hidden in our genetic past. As his latest book, A Brief History of Everyone Who Ever Lived, uncovers what history can tell us about our genes and what our genes can tell us about history; in an exclusive article for Waterstones he reveals a royal secret hidden in everyone’s history.

Family: the ties that bind us to our pasts. There’s our immediate kin who provide context for a lived life. And there’s evolution, which places us as an infinitesimal sprig on the grandest tree of all. In between these two pillars of life lies genealogy.  It’s the most popular pastime in the US, and the second most popular in the UK (gardening remains our national hobby). The highly entertaining BBC television programme Who Do You Think You Are? has played a large part in the increasing popularity of genealogy in the last few years. In it, celebrities, with the assistance of expert genealogists, trace paths in their family trees and uncover interesting characters from their families. Frequently this is very moving, or powerful, such as when the television presenter Natasha Kaplinski discovered that many of her ancestors had been murdered by Nazis. 

Other times it’s decidedly amusing. In 2016, the opening episode of the 10th series of Who Do You Think You Are? featured the British actor Danny Dyer. He typically plays a lovable east end rogue, a sort of cockney wideboy, which in some ways reflects his working class roots from Canning Town in east London. He is probably best known for being the landlord of the Queen Victoria pub in the long-running BBC soap Eastenders. In the final moments of this episode, having tracked back through centuries of his family tree, it was revealed, with great dramatic splendor that Danny Dyer is directly descended from King Edward III. The first Plantagenet king of England is Danny Dyer’s 22 times great grandfather.

His reactions were quite hilarious; utterly and sincerely gobsmacked, he commented ‘I need to get it in my nut, then move on with my life,’ followed by ‘I’m going to treat myself to a massive ruff’ (let us forgive him this anachronism – ruffled collars or ruffs were a fashion that began in the mid-16th century). He then said ‘My blood is his blood, I can’t compute it in my brain.’ 

As I was watching, I was left wondering if I could. More specifically, I was pondering the probability that I or indeed anyone born in the 1970s was also descended from Edward III. In order to figure that out, I corresponded independently with two colleagues at University College London, geneticist Adrian Timpson, and mathematician Hannah Fry, on two different methods. The answers came out roughly the same, and what follows complies with the eternal maths exam instruction ‘Show your working’:

To make it as accurate as possible, we elected to count how many descendants Edward III had, until the number becomes fuzzy, and estimate the number of ancestors someone born in the 1970s would have at the same point in history. The question then becomes ‘what is the probability that any of your ancestors at that time were in the proportion of the population who were direct descendants of Edward III?’

Edward was born on the 13 November 1312. He was a powerful king, and in his 50-year rule, oversaw brutal war with France, the Black Death and many changes in British life that persist to this day: the separation of the House of Commons from the Lords; the establishment of Scotland as an independent nation. He died aged 64, and between him and his fecund wife Philippa of Hainault, they had 13 children, six of whom had children themselves, including Kings Richard II and Henry IV. I counted a total of 321 great great grandchildren, which is a sizeable brood, but far from impossible. The trees become a bit vague after this, but we conservatively estimated that if each of these on average had two children, then Edward would have a total of around 20,544 descendants in the year 1600CE. The population of Britain at that time was around 4.2 million, which means that around 1 in 210 people were direct descendants of Edward III – approximately 0.5 per cent of the population. 

Now, working backwards from 1975, the year of my birth: the standard assumption is that people reproduce every 25 years on average, which means that  there will have been 15 generations between 1600 and 1975. You have two parents, and they had two parents and so on, two by two, so the number of ancestors doubles each generation working up your family tree, meaning that by 1600, one person should have 32,768 ancestors. This assumes full outbreeding, which is very unlikely – we’re all inbred over a long enough period – but for our purposes makes little difference. 

Therefore, each one of your 32,768 ancestors in the year 1600 has a 0.5 per cent chance of being direct descendants of Edward III. If you reverse the question, and ask ‘what are the chances that none of your 32,768 ancestors in 1600 are in that 0.5 per cent’, the calculation becomes 

0.995 x 10^32,768 = 4.64^-72 

Which is an absurdly small number.

And to get the answer to the original question, we subtract that from 1, which comes to 

0.999999999999 (etc).

What this means is there is a virtually impossible chance that if you were born in the 1970s then you are not directly descended from Edward III. Now, this is an estimate, and the error margins are huge. It largely applies to people whose ancestry has a significantly historical British component, so not to Brits whose deeper family origins are rooted elsewhere in the world. For me it works on my paternal side – dad born in Yorkshire - but not for my Indian mother. As this whole book attempts to show, people are suboptimal experimental animals, and family trees as untidy as a teenager’s bedroom. Nevertheless, the numbers come out so significantly, that even if these estimates are several orders of magnitude wrong, they still show the same answer.

Family trees expand upwards and outwards from you, but soon enough they collapse in on themselves, and become matted webs. There are no pure lineages, by blood or genes; you are as equally related to King Edward III as Queen Elizabeth is. This mathematical proof is not the same as being able to show it using certificates of births, deaths and marriages, as both the Queen and Danny Dyer can, but it is no less true. If you have broadly British ancestry, you are descended from Edward III. And all of his regal ancestors too, including William the Conqueror, Æthelred the Unready, Alfred the Great, and as shown in Chapter 3, literally every 10th century European ruler. 

You may now treat yourselves to a massive ruff.

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