King Richard III
Turi King led the genetic and statistical analysis in the King Richard III case.
For more information about the project, please follow this link www.le.ac.uk/richardiii
Are you related to King Richard III?
Yes! It’s simply a matter of degree.
Richard III has no known living descendants but it is known that there are people alive today who are descended from his family. Benedict Cumberbatch is just one of them of what is estimated to be between 1-17 million people alive today who can claim a similar relationship to Richard III! You can read more about that in an article written by Turi here.
However, because of the way our DNA is passed down through the generations and the number of generations since King Richard III was alive, it may not be possible to use DNA to prove that link.
The vast majority of our DNA is a complex mixture of that of our ancestors. There are only two segments of our DNA that are passed down through the generations in a simple way: these are mitochondrial DNA and the Y chromosome. Both of these segments of our DNA are passed down through the generations virtually unchanged save for the gradual accumulation of mutations. These mutations can be thought of a typos in the DNA sequence. We geneticists like these typos because it gives us a way to tell people apart from one another and also look for people who are related to one another. However, they are only passed down through the generations in a particular way! See below:
Mitochondrial DNA is a small circular piece of DNA that is passed down to us by our mothers. As it’s in the egg, mothers pass it down to all of their children but because boys have sperm, not eggs, only daughters pass it on.
This meant that if we could find living individuals who were related to Richard III through this all-female line then we could compare the mitochondrial DNA from these individuals with that of the putative remains of Richard III to look for a match. And it didn’t matter if that link when up the genealogical tree and back down again to Richard, as along as the link was an all-female one, and its find to have boys at either end of that chain, then DNA that the living relatives provided us could be used to make the identification.
But is also means that as soon as a genealogical link back from a living individual to Richard III passes from a mother to a son, then that genetic link is broken because the son won’t pass on his mitochondrial DNA and DNA analysis can’t be carried out to prove a link.
The Y chromosome
We humans have 23 pairs of chromosomes, and one of these pairs is known as our sex chromosomes. They only come in two flavours, known rather unexcitingly, as X and Y. Women have two copies of the X chromosomes where as men have an X and a Y chromosome. The Y chromosome has a gene on it which switches on during development and starts the embryo down the path to becoming a boy – it is passed down by a father to sons only.
This meant that if we could find living individuals who were related to Richard III through this all-male line then we could compare the Y chromosomes from these individuals with that of the putative remains of Richard III to look for a match. And it didn’t matter if that link when up the genealogical tree and back down again to Richard, as along as the link was an all-male one, with no women in the genealogical chain, then DNA that the living relatives provided us could be used to make the identification.
But is also means that as soon as a genealogical link back from a living individual to Richard III passes from a father to a daughter, then that genetic link is broken (because the daughter won’t inherit her father’s Y chromosome, and DNA analysis can’t be carried out to prove a link.
Another tiny possible problem: the issue of false-paternity
The Y chromosome that a man inherits is that from his biological father, who might not be the recorded father. This is known as false-paternity. If this happens, the the genealogy may show one thing but the DNA will show another (unless the false paternity occurred with a close male-line relative of the recorded father. Is is known that false-paternity occurred at a level of about 1-2% per generation historically and therefore this is not an uncommon find.