How many people descend from royalty

This I find relatively easy to digest. The simple logic is that there are more living people on Earth now than at any single moment in the past, which means that many fewer people act as multiple ancestors of people alive today. But how can we say with utter confidence that any individual European is, like Christopher Lee, directly descended from the great European conciliator? The answer came before high-powered DNA sequencing and ancient genetic analysis.

Instead it comes from mathematics. Joseph Chang is a statistician from Yale University and wished to analyze our ancestry not with genetics or family trees, but just with numbers. By asking how recently the people of Europe would have a common ancestor, he constructed a mathematical model that incorporated the number of ancestors an individual is presumed to have had each with two parents , and given the current population size, the point at which all those possible lines of ascent up the family trees would cross.

The answer was merely years ago. If this sounds unlikely or weird, remember that this individual is one of thousands of lines of descent that you and everyone else has at this moment in time, and whoever this unknown individual was, they represent a tiny proportion of your total familial webbed pedigree. A thousand years in the past, the numbers say something very clear, and a bit disorienting. One-fifth of people alive a millennium ago in Europe are the ancestors of no one alive today. Their lines of descent petered out at some point, when they or one of their progeny did not leave any of their own.

Conversely, the remaining 80 percent are the ancestor of everyone living today. All lines of ancestry coalesce on every individual in the 10th century. The math that falls out of that apparent impasse is that all of the billions of lines of ancestry have coalesced into not just a small number of people, but effectively literally everyone who was alive at that time. So, by inference, if Charlemagne was alive in the ninth century, which we know he was, and he left descendants who are alive today, which we also know is true, then he is the ancestor of everyone of European descent alive in Europe today.

The fact that he had 18 increases the chances of his being in the 80 percent rather than the 20 percent who left no 21st-century descendants, but most of his contemporaries, to whom you are all also directly related, will have had fewer than 18 kids, and some only one, and yet they are all also in your family tree, unequivocally, definitely, and assuredly.

DNA says exactly the same thing as mathematical ancestry: Our family trees are not trees at all, but entangled meshes. With the advent of easy and cheap DNA sequencing came the possibility of testing this math. DNA is the bearer of biological ancestry, and you get all of your DNA from your two parents, pretty much a split. They in turn got all of their DNA from their parents, so one quarter of your DNA is the same as a quarter of each of your grandparents.

If you have a cousin, then you share around an eighth of your DNA, as you have a pair of grandparents in common. These shared bits of DNA are not the same sections though. In the newly shuffled deck, that is, your own personal genome, big chunks of it are the same as your father or mother. The more closely related two people are, the more DNA they will share in big chunks.

This is why identical twins are identical all the chunks are the same , and why siblings and parents look similar half of their DNA is the same as each other. In genetics, we call these sections of DNA identical by descent, and they are very useful for measuring the relatedness of two individuals.

They looked for lengths of identical by descent DNA in 2, people from around Europe to mitigate the influence of recent migration, all the subjects selected had four grandparents from the same region or country.

By measuring the lengths of the shared DNA, they could estimate how long ago that deck got shuffled, and therefore how related any two people are. Computing and DNA have empowered this field, and this is shown in their dataset and the number crunching that follows.

By the time Cornelis Drebbel built an oven with a simple thermostat, one of the first manmade feedback mechanisms in history, in the s, he was regarded in Europe as a magisterial, if not mad, inventor.

He had already enchanted We typically marry within socioeconomic groups, within small geographical areas, within shared languages. Ancestry is such that genes can spread very quickly over generations. It might seem that a remote tribe would have been isolated from others for centuries in, for example, the Amazon.

But no one is isolated indefinitely, and it only takes a very small number of people to breed out with people from beyond their direct gene pool for that DNA to rapidly descend through the generations. Chang factored that into a further study of common ancestry beyond Europe, and concluded in that the most recent common ancestor of everyone alive today on Earth lived only around 3, years ago.

All this means is that as you move back through time, sooner or later some of the lines in the genealogy will cross, meeting at a single person. As you go back further in time, more of those lines cross as you encounter more common ancestors of the living population. And then something really interesting happens. The most recent common ancestor of every European today except for recent immigrants to the Continent was someone who lived in Europe in the surprisingly recent past—only about years ago.

In other words, all Europeans alive today have among their ancestors the same man or woman who lived around Suddenly, my pedigree looked classier: I am a descendant of Charlemagne. Of course, so is every other European. And so are you, and everyone else on Earth today. Chang figured that out by expanding his model from living Europeans to living humans, and getting an estimate of years instead of a thousand for the all-ancestor generation.

Things have changed a lot in the fourteen years since Chang published his first paper on ancestry. Scientists have amassed huge databases of genetic information about people all over the world. These may not be the same thing as a complete genealogy of the human race, but geneticists can still use them to tackle some of the same questions that intrigued Chang.

They took advantage of a compilation of information about people from across the continent. Each time they made eggs or sperm, they shuffled the two copies of each of their chromosomes and put one in the cell. Just as a new deck gets more scrambled the more times you shuffle it, chromosomes get more shuffled from one generation to the next. Ralph and Coop identified 1. They then used the length of each segment to estimate how long ago it arose from a common ancestor of the living Europeans.

Instead, someone in Turkey and someone in England have to share a lot of ancestors. In fact, as Chang suspected, the only way to explain the DNA is to conclude that everyone who lived a thousand years ago who has any descendants today is an ancestor of every European.

Charlemagne for everyone! Since they live in the same country, chances are they have more recent ancestors, and more of them. But there is a rich, intriguing pattern to the number of shared segments among Europeans. People across Eastern Europe, for example, have a larger set of shared segments than people from within single countries in Western Europe. But genetic testing is starting to make a more significant contribution to efforts to establish the existence of royal relatives.

Other well documented descendants of the House who are alive today have taken a DNA test to identify genetic markers unique to the Stewart family that are carried by the Y-chromosome, part of the DNA passed down to every male descendant.

So now any man who wants to find out if he is a distant relative as opposed to descendant of Mary Queen of Scots can take a Y-DNA test to see if there is a match, although the results will only reveal whether the subject is at the end of an unbroken male line of descendants. The same principles apply to other royal and noble families and clans , and instances of descent from Robert the Bruce have been proved this way. Both men and women can also take an autosomal DNA test , which looks at the rest of the chromosomes for genetic matches with other people who have taken the test.

In theory, this could also reveal you descend from royalty as you may share the same genetic ancestor with someone who has a documented royal ancestry. Despite this, DNA testing has made medieval genealogy for the masses a real possibility. Festival of Social Science — Aberdeen, Aberdeenshire.

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