Surnames, Yorkshiremen and Y-Chromosomes
Kat - Hi Turi, the last time I saw you was on TV! You were talking about this research looking at how genes are spread through populations and where we've come from, so can you tell us a little more about the study where you've found African genes in Yorkshire?Turi - That's right. Actually, what I've been doing has been part of a larger PhD project which was funded by the Wellcome Trust, it's been looking at the link between Y-chromosomes and surnames. The interesting thing that we're looking at here is that the Y chromosome is just passed down from father to son, and surnames are also passed down from father to son so you might think that there may be a link between a type of Y chromosome and a particular name. There are a lot of things which can break this link, the obvious one is illegitimacy, where you have one man's Y chromosome type but another man's surname, adoption will do the same sort of thing. The other thing is numbers of founders for a particular surname, so if you were to look into the surname 'Smith' there's going to be a number of different founders for that particular surname because it comes from 'Blacksmith'. You would expect a number of different Y chromosome types associated with that surname. If you look at rare surnames you find that quite often there's just a single Y chromosome type or just a handful associated with that surname. One of the surnames I looked at was Attenborough (as the two alternative spellings - Attenborough and Attenborrow), 87% of them, regardless of spelling variant, are descended from one individual. There are a handful of other Y chromosome types associated with the name, but we don't know if they are illegitimacies, adoptions or other founders who happen to have had fewer descendants.Kat - So tell us about the research in Yorkshire; you found a family, or people with a Yorkshire surname, and I understand they're a white population but they have African ancestry. How did you find that out?Turi - Originally, when I was just starting the PhD we put advertisements in local newspapers and about 421 men responded. I was typing their Y-chromosomes expecting to come across all the typical European ones you would expect to find and I came across this really unusual type. I showed it to my supervisor, Mark, and we thought that maybe we'd made a mistake, so we tested it more, and found out that it belongs to a really rare African Y chromosome type that's only found in West and North Africa and there's only 26 other cases of it in the world, all of which trace back to this confined space. So then we decided to look at the surname; are there other people with this surname who've got this Y chromosome type so I recruited another 18 men and 7 of them had this rare Y chromosome type. We knew they all had to be related, we just didn't know how, so we commissioned a genealogist to look at their family trees and they managed to trace two family trees back to 1788 and 1789 but they couldn't join them up. They all originated in Yorkshire and looking at the genealogical evidence and the genetic evidence they probably join up in the early 18th century. Kat - So how does this fit in with the history of black people in Britain? Where do you think this originally came in to the gene pool?Turi - Well there are a couple of really obvious routes, one is the Romans, as they had a garrison of Moors who were guarding Hadrian's wall in AD 200, so that's a possibility. More likely is the slave trade, as you had the first Africans arriving in this country in 1555. Again, West Africa is where a lot of the slave trade came from and with the sheer numbers of West Africans coming into the country as domestic servants you would expect that to be the most likely route.Kat - So where do you go from here? Do you have another project on the go already?Turi - Well I'm writing up a PhD at the moment! One of the other things that came out of the research was that because there's so much sharing of Y chromosome types within surnames, particularly rare ones, you can actually use a Y chromosome type to predict a surname. I did this as a small pilot study using 150 different surnames; I took 2 guys at random from around the country who had one of these surnames and I looked to see how often they shared a Y chromosome type and I found that, if you take two 'Smiths' at random they don't tend to share a type, but if you take two 'Revis' for example, then the chances of them sharing a Y chromosome type is actually quite high. So out of this small pilot project I found that I could predict, across the board, correctly using just the Y chromosome type 19% of the time I could predict the correct surname. If you just use the rare half of the surnames, the lower 75, it goes up to 34% accuracy. There's implications in this for using it as an investigative tool for the police, whereby they could put in a Y chromosome type collected from a crime scene and get it to bring out surnames, which could help with prioritising a list of suspects. It would never replace standard research, it's just an investigative tool as a way of prioritising suspect lists, but it could be quite powerful in terms of cutting investigation times.Kat - I think our Dr Dave, being an Ansell, has got quite a rare name...Turi - In fact, I've got my surnames dictionary here and so I can look it up! Ansell... English, chiefly East Anglia, from a Germanic personal name, composed of the elements Ans 'God' and Helm 'Protection' or 'Helmet', so 'Godhelmet'...Kat - I think we'll have to start calling Dave 'Godhelmet' from now on...Turi - I think you should! It was bought to France by a famous medieval churchman, apparently.Kat - Well we won't be able to do that with Dr Chris, because he's Chris Smith, so a common surname. But what else can Y-chromosomes tell us about populations, because obviously it doesn't work for women...Turi - No, it doesn't. It just tells you about the male half of the population, but it's quite a nice, compact piece of DNA which doesn't much from father to son so it gives you a nice clear record of our male ancestry. Like looking at markers such as M17 found in higher frequencies in Norway than elsewhere, its a nice way of saying; 'you've got a particular type of M17, so you have a higher chance of having ancestry from there.'