What follows is a summary of a pilot genetic study carried out in the Wirral and West Lancashire and all references to the Wirral and West Lancashire study refer to the publication by Bowden, et al. (2008). The aim of that study was to examine the genetic legacy of the Vikings in the Wirral and West Lancashire using modern samples. Thus we wanted to collect DNA from those who have the deepest ancestry in the area where Vikings settled. So how to find those individuals? Certainly the standard approach of sampling individuals with two generations of ancestry in the area would at least get around the problem of very recent immigration to the area. But to find individuals with deeper ancestry in the area a new selection approach suggested itself, the foundation of which rests on the tight link between surnames and the Y chromosome. So let’s examine these two linked elements in turn.
Surnames
The practice of using hereditary surnames was brought to Britain by the Normans following the invasion of 1066. In France, family names had been in use by the aristocracy for a couple of generations. As they had in Normandy, the Norman lords here used them as a way of solidifying claims to land and ensuring inheritance and therefore the first hereditary surnames were often derived from place-names, e. g., Roger de Poitevin (McKinley 1990). Hereditary surnames in England were first adopted by the wealthy landowning families, and the use of them then gradually filtered down to the rest of population becoming commonplace in the south earlier than in the north of the country. For many years, however, people still had non-hereditary bynames and it wasn’t until 1350AD that many families had surnames with it becoming rare not to have a surname by 1500AD (McKinley 1990, Redmonds 2004, Hey 2000). This gives an average age for surnames of ~700 years.
The surnames that people used came from a variety of sources broadly grouped into six categories. Many surnames derive from first names, usually from the father, with a child being known as theirs, giving us surnames such as Johnson and Roberts. Other surnames derived from a person’s occupation (Smith, Thatcher), or nicknames, (Jobling, Brown) from how a person looked or behaved, from a relationship (Cousins). Others got their surnames as a way of indicating where they came from (locative surnames from a place (Raby, Lancaster) or where they lived (from topographical features of the landscape (Beck, Bush). Some surnames have multiple derivations, for example being derived from both a personal name and a place name (Redmonds 2004). Thus each surname in your family tree carries with it a story about a feature of an ancestor’s life.
Two interesting characteristics of surnames are their large overall number and their individual rarity. The 1881 census listed over 400,000 surnames, a number which is thought to be even greater now, mostly as a result of immigration. Perhaps unsurprising then is the fact that most surnames are rare: the most frequent 500 surnames are carried by ~45% of the population meaning that the vast majority of surnames have only a small number of carriers. Indeed the average number of carriers for a surname is around 70 people. Finally, while some surnames (particularly the common ones) are found across the country, many surnames have a ‘home’ where the surname originated potentially many hundreds of years ago and around which most people with the surname still live today. Thus a person’s surname often contains within it information about where his or her family can trace their ancestry back to.
The Y Chromosome
The nexus between the field of surname history and genetics arises in the form of a particular piece of our DNA: the Y chromosome The job that the Y chromosome does has an impact on how it is inherited: it can, because it carries the gene that determines maleness, only be inherited from father to son and therefore the Y chromosome that a man carries is essentially that of his father, which was that of his father and so on back through time.
Not all men have the same Y chromosome. Mutations, errors in the DNA sequence that are generated when the Y chromosome is being copied, are passed down to the next generation, introducing variation in the types of Y chromosomes seen among men. Perhaps the easiest way to think of this mutational process is to think of the Y chromosome as a story that is told by a father to his male offspring. We know the story originated in Africa over 100,000 years ago and since this time, fathers have passed down the story through the generations. Sometimes a father would change the story very slightly when telling it to one of his sons and this son in turn would tell this new version of the story to his male offspring, such that now it is possible to find different versions of the same story in different parts of the world, and with more closely related men having their own more similar versions of the story. Geneticists are able to use molecular tools to determine what a man’s Y chromosome story (type) is.
One might expect then that as surnames became heritable, both a man’s surname and his Y chromosome type would be passed down through the generations hand in hand such that if only one man took on particular surname many hundreds of years ago, then all men alive today with that surname should be descended from him and have his Y chromosome type (or a very similar one). If this were indeed the case, that a link exists between a surname and a particular Y chromosome type, then sampling men with old surnames from the Wirral and West Lancashire should give a better representation of the types of Y chromosomes found in those regions, ~700 years ago.
A Link between Surnames and the Y Chromosome?
At the outset it could be surmised that, at least for common surnames, it was unlikely that there would be a simple link between a surname and a single Y chromosome type. For surnames such as Smith, from the occupation of blacksmith, and with the likelihood of there being a blacksmith in most towns and villages, the surname would have been taken on a number of different times, by different men, all with their own individual Y chromosome types which they would then pass down to their male-line descendants. But what about rare names? As we know, most surnames are rare: did each one have just one Y chromosome type associated with it; that, presumably, of the original founder several hundred years ago? With an average surname-age of 700 years would we still find a link after all this time? Perhaps events such as illegitimacy (where a child would have one man’s surname but another man’s Y chromosome) or adoption, or inheriting the mother’s surname would break the link between a surname and a Y chromosome type. Other factors will affect the types of Y chromosome associated with any one surname today. Genetic drift, the difference in the number of male offspring that men have, means that some men will have many sons, passing on their surnames and Y chromosomes many times whereas, at the other end of the spectrum, other men will have no sons to carry on their surnames and Y chromosome types: a phenomenon known as ‘daughtering out’ in genealogical circles. Finally, we know that tiny mutations (changes in the story) would have occurred on the Y chromosomes in a true lineage over time which would have to be taken into account. How would all these factors affect the types and number of Y chromosomes types associated with a surname?
The Surnames Studies: The 'Pairs' and 40 Surnames Studies
The first step was to do a ‘pairs’ study asking the question: what do we find when we take two men at random from around the country with the same surname but who don’t know themselves to be related? Do they also have the same Y chromosome type with both their surname and Y chromosome type being descended from the same ancestor? To carry out the pairs study, surnames were chosen from across the frequency spectrum, from very common names (Smith) down to lower frequency names (Rivis—with only 50 people carrying this surname in Britain). 150 pairs of same-surnamed men were collected and their Y chromosomes analyzed using 17 STRs and 13 SNPs and it was found that overall, 24% of the pairs appeared to share a common ancestor through their surname. Given that we expect common names to have more than one founder (and so two men taken at random with a common name might not be expected to have inherited their surname and Y chromosome from the same ancestor) it was interesting to look at the lower half of the frequency spectrum where surnames are more likely to have had a single founder: here just under 50% of the pairs had results consistent with them sharing a common ancestor through their surname. Thus despite the length of time since surnames were established and all the factors that could affect the link between surname and Y chromosome a link existed and that link was stronger the rarer the name. An in-depth study of 40 surnames (with known spelling variants) using the same STRs and additional SNP markers then followed where many men with the same surname, but who did not know themselves to be related, were recruited. A similar pattern was seen. Among the common names, very few men appeared to be related. However, when looking at middle frequency surnames, ‘descent clusters’ began to appear: groups of men with the same surname (or with surname spelling variants) who had identical or near identical Y chromosome types suggesting that they all shared a common ancestor through their surname. The picture was even more striking among the rarer names. It was often the case that a single surname was dominated by a single Y chromosome type with related types. These were large groups of men who were apparently unrelated but the genetic analysis proved that they all shared a common ancestor through their surname. The best example from the set is provided by the surname Attenborough (with the spelling variant Attenborrow) where 31 men from around the country bearing either of these names, and who did not know themselves to be related, were sampled. Out of these 31, 27 had identical or near identical Y chromosome types such that they all form part of an as-yet-to be constructed family tree. Thus both studies gave the same result: a strong link exists between surname and Y chromosome type with the link being stronger the rarer the name (King et al., 2006; King and Jobling, 2009, 2009a; Redmonds et al., 2011).
Thus the link between surname and Y chromosome provides us with a method to sample men with deep ancestry in an area putatively back to the time when hereditary surnames were being adopted. So how to apply this surname sample method? It is important to point out that the Vikings did not use hereditary surnames and that the use of hereditary surnames in this country did not become widespread until hundreds of years after the Viking rule.. In Ireland, where the early period of surname adoption overlapped that of the Viking period, this provided an opportunity for sampling men carrying Irish surnames thought to have Norse roots. One small study sought to do just this, sampling men bearing surnames thought to have putative Norse origin, though the results did not suggest substantial Scandinavian ancestry among them.
World History
