DNA and Social Networking E-Book

Debbie Kennett

• Herausgeber: The History Press
• Kategorie: Geisteswissenschaft
• Sprache: Englisch

Veröffentlichungsjahr: 2011

Beschreibung

The first decade of the new millennium has been an exciting time for the family historian. The increasing availability of online resources has transformed the genealogical research process. DNA testing and the new generation of social networking websites have developed in parallel and are becoming increasingly useful tools. DNA testing can now be used to prove or disprove genealogical connections and will put you in touch with your genetic cousins around the world. It can also take you back beyond the paper trail into your pre-surname history. Social networking tools can help you to find and stay in touch with friends and relatives, and provide new ways to share and collaborate with other researchers. This book looks at all the latest advances in DNA testing from the Y-chromosome tests used in surname projects through to the latest autosomal DNA tests. Debbie Kennett explores the use of new social media, including Facebook, Twitter, blogs and wikis, along with more traditional networking methods. DNA and Social Networking is an indispensable guide to the use of twenty-first-century technology in family history research.

Leseprobe

Contents

Title

Forewordby Chris Pomery

Preface

Acknowledgements

I THE GENETIC GENEALOGY REVOLUTION

1

The basic principles

2

Surnames and the paternal line

3

Before surnames: haplogroups and deep ancestry

4

The maternal line: mitochondrial DNA tests

5

Cousins reunited: autosomal DNA tests

6

Setting up and running a DNA project

II THE SOCIAL NETWORKING REVOLUTION

Introduction

7

Traditional genealogical networking methods

8

Genealogy social networking websites

9

General social networking websites

10

Blogs

11

Wikis

12

Multimedia

13

Collaborative tools

Appendix A

DNA websites

Appendix B

Testing companies

Appendix C

DNA projects

Appendix D

Surname resources

Glossary

Bibliography

Copyright

Foreword

by Chris Pomery

This book is timely as it catches family history at a point where it is changing from being predominantly a solitary pursuit and becoming more and more a group endeavour. The networking methods that Debbie reveals in this book – and the collaborative skills that she teaches – can be used by every genealogist to help widen our searches and accelerate our research.

We’re all aware that the last decade has seen an explosion in the amount of family history data arriving online. The days when most genealogical research started out with day-long trips to record offices armed with a notepad and pencil have now passed. Today the first place people look when they begin their research is on the web. This has to be a good thing. More people have access to the data, they have equal access to it and they can access it from anywhere around the world at any time they choose. These changes have also led to an increase in the number of people researching each source, and to many more people placing the results of their research online, either as a tree, a website or even simply as a note on an online bulletin board.

While some research is always going to be of a less than high quality, the increased sharing stimulated by the web helps each of us to move our own research forward quicker. That’s a clear improvement on the pre-email past, but the main benefits of the internet age are truly found when we learn to work together; building up a team of researchers and collaborators who by working together achieve more than any one individual ever could, and more quickly. This book explains how everyone can start to reap the benefits of that networking process, regardless of whether you’re running a DNA project or not.

A major section of the book you’re holding describes the latest developments in the fast-changing field of genetic testing for genealogists. Next to the arrival of the internet, the application of genetic tests for use by family historians is the second great genealogical revolution of the past decade. Long used by population scientists to unravel how mankind spread across the planet from our origins in Africa, we now have ten years’ experience of using DNA testing to advance our family history research.

Today many thousands of DNA projects are currently underway around the world; run by ordinary people like you and me, the vast majority of them analysing whether men who share the same surname are genetically related to each other and, therefore, belong in the same family tree. The pool of around half a million Y-chromosome DNA results that has now been built up is helping each of us develop a clearer picture of how our surnames came into being, how and why they grew as they have done and how related we are to each other.

Genetic testing increasingly looks set to become an integral part of everyday genealogical research in the years ahead. A decade ago, a DNA test was seen as something exotic and tangential to the main work of the genealogist, which was visiting archives and transcribing the data in them. Today it’s possible to run a parallel DNA project and to use the DNA results to confirm we have identified the correct people within each line and tree. While the first generation of tests looked only along two of our many lines – the direct paternal and maternal lines – the good news is that the new, second generation of DNA tests is going to be even more useful, as they help identify anyone who descends from any one of our great-great-grandparents.

This is a book that has been waiting to be written, and Debbie is the right person to write it. Well known within the Guild of One-Name Studies as an expert on social networking, she has been promoting her own surname DNA project, which is investigating the origins of the West Country surname Cruwys, for many years. This book summarises her experience in a highly readable format, which serves both as a primer for family history researchers, and as a resource that anyone can dip in to in order to learn more about social and online networking, and about DNA testing.

www.DNAandFamilyHistory.com

Preface

The first decade of the new millennium has been an exciting time for the family historian. I took my first tentative steps on the internet in December 2000 and one of the first searches I performed on Google was for the surname Cruwys (pronounced Cruise), my own maiden name. There were probably no more than a few hundred results and I was able to work my way right through to the end of the search list. A similar search today returns around 30,000 hits. When I first started to research my family history I purchased censuses on CD and microfiche, and scrolled through reels of microfilm at the library. Now all the UK censuses from 1841 through to 1911 are transcribed and indexed and, for the price of a subscription to a commercial provider such as Ancestry.com or Findmypast, digital images of the original census pages can be viewed online or downloaded on to a home computer. New datasets, such as wills and parish register collections, are being added on a regular basis and the challenge now is that there is so much available on the internet that it is difficult to find the time to search through all the new records. The increasing availability of online records has in turn fuelled a growing interest in family history research in the UK, helped in part by the popularity of television programmes such as Who Do You Think You Are? which first hit our screens back in 2004.

The world of genetic genealogy

DNA testing has developed in parallel to these new developments in the family history world. The first commercial DNA tests for genealogists became available in the year 2000, the same year in which scientists published the first draft of the human genome. By the end of 2001 there were about 100 or so DNA projects in existence. Four years later the number of projects had grown to over 2,500. By the end of the decade there were well over 6,000 projects. I first became aware of the possibilities of DNA testing when I joined the Guild of One-Name Studies in 2006. Two Guild members, Susan Meates and Chris Pomery, were among the early pioneers of DNA testing. Susan published a series of articles in the Guild’s journal on the Meates DNA project, and Chris had already published his first book on the subject with a second to follow in 2007. I set up my first project for my Cruwys/Cruse one-name study in September 2007. There are distinct advantages in being one of the second-phase adopters of a new technology. I was able to draw on the collective knowledge of my fellow Guild members and other project administrators, both here and in the US, and learn from their mistakes and experiences. If ever I had a difficult question or an unusual result there was always someone who could provide the answer. Boosted by the success of my surname project, in March 2009 I set up a new DNA project for the county of Devon, and later that same year I became a co-administrator of the mitochondrial DNA haplogroup U4 project. I now have responsibility for over 550 project members, which has given me a very broad insight into the range of results that might be expected across the full spectrum of tests. I learn more as each new result comes in and, through the process of explaining DNA test results to a large number of project members, I have come to understand the questions that can arise and the problems that people have understanding their results. In the few years since I have been involved in DNA testing the science has not stood still. New initiatives have been launched, new features have been added to existing products and a major new DNA test has been added to the toolbox for the family historian. I have been able to monitor these developments as they have happened and have tested either myself or members of my family as appropriate.

The first part of this book is devoted to this exciting new world of genetic genealogy. The book starts by explaining the basic principles involved and then goes on to look in depth at the three different DNA tests that have a direct application for the family historian. It is not necessary to have a degree in genetics to understand the results of a DNA test, but there are just a few key pieces of terminology that need to be mastered. As with any new tool, it is all very well understanding the theory, but it is only when you start to put that theory into practice and take a DNA test for yourself that it begins to make sense. I hope that I have explained the benefits sufficiently well to encourage you to take that important first step if you have not already done so.

Making connections

The rapid growth of the internet has not only transformed family history research but has also revolutionised the process of making contact with other researchers from all over the world. There is only so much that one person can achieve on his or her own, and the research process becomes much easier and more productive if you can share the burden and collaborate with other researchers. Not all the answers can be found on the internet and you will also want to track down living people to fill in some of the gaps in your own genealogical jigsaw puzzle. Another family member might have a copy of the long-lost family bible, an archive of family photos or a collection of handwritten letters that will add context to your research. If you become involved in a DNA project you will have a particular interest in tracking down living relatives or other people who share your surname as you will hope to persuade them to participate in the project. The second part of this book therefore looks at different ways to network and collaborate with other researchers. If you are contemplating setting up your own DNA project you will be able to use some of these methods to promote your project. Some of the websites covered are designed specifically for the genealogist, but the mainstream social media websites also have an important role to play. If you are trying to get to grips with these developments for the first time it can be very difficult navigating the internet to find the most relevant sites. I have, therefore, provided a comprehensive collection of links at the end of each chapter for background reading and further information.

The ephemeral nature of the internet means that there is no guarantee that all the websites I have featured or listed will still be in existence by the time you read this book. Similarly, there will no doubt be other innovative new websites on the horizon which I have not anticipated. In writing this book I have made full use of all the new social media to keep me informed of the latest developments, but it has been quite a challenge keeping up with all changes. New social networking websites were being launched, existing websites underwent major redesigns and once-popular websites fell out of favour and were closed down. New companies appeared on the scene while others were taken over or went into liquidation. New DNA tests were introduced to the market and new features were added to existing tests. Inevitably in a book of this nature there will be omissions, for which I take full responsibility. If you feel that I have missed out something important I would love to hear from you, and I would hope to rectify any errors in an updated edition of the book in the future. Regardless of any errors, omissions or subsequent developments, the basic principles and techniques described in this book will still apply.

I have assumed that anyone who is motivated to read a book on DNA and social networking will already have some knowledge of the basic principles of family history research. The wider topic of surnames is also beyond the scope of this book, but there are a number of excellent books on the subject and I have included a comprehensive list in the bibliography, together with a list of surname websites in Appendix D.

I hope that you will share my enthusiasm for DNA testing and social networking, and that by the time you have finished this book you will be inspired to get your own DNA tested and to make the most of all the social networks to help with your own family history research.

Acknowledgements

I am fortunate that I joined the world of DNA testing at a time when genetic genealogy had already come of age. We owe a huge debt to the scientists who made it all happen, and to the pioneering project administrators who embraced this new tool from the beginning and shared their experiences in books, magazine articles and on mailing lists and websites. This book would not have been possible without them and I have merely distilled the combined knowledge of my predecessors to bring the subject up to date.

I am very grateful to Chris Pomery for writing the foreword to this book, and for all his encouragement over the last few years. Tim Janzen kindly read the draft of the DNA section and provided many helpful comments. John Sloan gave me some useful insight and commentary for the Y-DNA chapters. I enjoyed many friendly discussions with James Irvine and Ralph Taylor on the subject of surname distributions and the management of large surname DNA projects. Susan Meates was one of the early pioneers of DNA testing within the Guild of One-Name Studies, and I have benefited from her advice and experience. Ron Scott, my co-administrator on the U4 project, has been an invaluable source of knowledge on the topic of mitochondrial DNA testing. Princess Maria Semeonovna Sviatopolk-Mirski generously shared with me the results of her unique mitochondrial DNA test. Jill Whitehead provided an interesting perspective on Jewish DNA. Wendy Archer set me straight on the subject of mailing lists and message boards. Tom Hutchison collaborated with me on the ISOGG (International Society of Genetic Genealogy) Wiki, and helped me to understand the technical aspects of wiki creation. Polly Rubery joined the blogging community at the same time as me, and was a friendly sounding board for my early blog postings.

Who Do You Think You Are? Live (WDYTYA), the family history show organised by the Society of Genealogists at Olympia in London, has become a meeting place for genetic genealogists from both sides of the Atlantic in recent years – largely thanks to the work of Katherine Borges, the director of the International Society of Genetic Genealogy, and Brian Swann, the England and Wales co-ordinator of ISOGG. I would like to thank both of them for the many enjoyable discussions we have had both over the phone and in person. I am also indebted to my genetic genealogy friends and colleagues in America who came over to England for WDYTYA and shared their knowledge and insights with us during the show and afterwards over drinks and dinner. My thanks go out to Emily Aulicino, Terry Barton, Doron Behar, John and Ann Blair, Max Blankfeld, Candy Jones Campise, L.A. Chancey, Bennett Greenspan, Michael Hammer, Kenny Hedgpeth, Linda Magellan, Derrell Teat, Megan Smolenyak, Johnna St Clair and Cynthia Wells.

The ISOGG project administrators’ mailing list is always a source of advice and knowledge, and I would specifically like to thank Roberta Estes, Colleen Fitzpatrick, Bill Hurst, Julie Frame Falk, Kathy Johns, CeCe Le Moore, Nancy Kiser, David Pike, John Robb, Ann Turner and Larry Vick for their helpful contributions.

I am grateful to the many family historians from around the world who have generously shared their research with me for the benefit of my Cruwys/Cruse one-name study. I am indebted to the 550 or so people from twenty-five different countries who have participated in my various DNA projects, and given me access to a wide range of DNA test results. There is nothing like trying to explain DNA results to other people to help you to understand the process yourself! I have had many enjoyable email exchanges with my project members and even had the pleasure of meeting some of them in person.

I would like to thank Penny Law from Family History Monthly for recommending me to the publishers, and Katharine Reeve for putting her trust in me and patiently waiting for the delivery of the manuscript long after the due date. Abbie Wood and Lindsey Smith from The History Press have worked hard behind the scenes to bring this book to fruition, and Lindsey has patiently dealt with all the many amendments that had to be made to keep the book as up-to-date as possible prior to printing.

Finally I would like to thank my family who are totally bemused by my interests in DNA and genealogy, and who will no doubt be relieved that normal life will now be resumed after the completion of this book.

I

THE GENETIC GENEALOGY REVOLUTION

1

The basic principles

… the idea that within each of our body cells we carry a tangible fragment from an ancestor from thousands of years ago is both astonishing and profound. That these pieces of DNA have travelled over thousands of miles and thousands of years to get to us, virtually unchanged, from our remote ancestors still fills me with awe, and I am not alone.

Bryan Sykes, Blood of the Isles

It is now over ten years since the first DNA tests for the family historian came on the market. DNA testing is no longer a tool deployed by a few brave pioneering surname project administrators, but is rapidly becoming an essential part of the research process for many genealogists. In the early years there were just a few basic low-resolution tests available at comparatively high prices from a handful of companies. In the intervening years the range of tests available has grown and prices have dropped to a more affordable level. The number of companies offering DNA tests has also expanded. Today around a million people from around the world have had their DNA analysed, either for genealogy purposes or to learn more about their deep ancestry. We have not yet reached the stage where a DNA test is ordered by everyone as a matter of routine when they begin their family history research, but most people are at least aware of the possibilities of DNA testing, even if they do not fully understand the process and have not taken a test themselves.

All humans share over 99.5 per cent of their DNA. It is the few differences in the remaining 0.5 per cent of our DNA which distinguish us from each other. A DNA test will look at those few genetic markers in our DNA that do vary from one person to another. In general terms the more DNA we have in common with another person the more closely related we are, and the more markers that can be measured the more accurately the relationship can be predicted. This brings us to the first important point which relates to all DNA tests. A DNA test on its own reveals very little. The value of the test lies in the comparison process, and the more people you can compare your results with the better.

Types of test

When the first genetic genealogy tests became available in the year 2000 there were two different types of test that could be purchased: a Y-chromosome (Y-DNA) test and a mitochondrial DNA (mtDNA) test.

A Y-DNA test explores the direct paternal line, that is, your father, your father’s father, your father’s father’s father, and so on back in time. In most cultures the Y-chromosome usually follows the same path as the surname. For this reason, the Y-DNA test is the most popular and most useful test, and is usually the first exposure that family historians will have to DNA testing. A Y-DNA test can only be taken a by a man, as only men inherit a Y-chromosome. Women who wish to explore their surname through DNA testing, therefore, need to recruit a male relative, such as their father, brother, uncle or cousin, to take a test on their behalf. The first Y-DNA tests only looked at 10 or 12 genetic markers. Today a standard Y-DNA test will analyse a minimum of 37 markers and it is possible to be tested on 100 or more markers.

A mitochondrial DNA test is a mirror image of the Y-DNA test and follows the direct maternal line – your mother, your mother’s mother, your mother’s mother’s mother. Both males and females inherit mitochondrial DNA from their mothers, but only the female can pass it on to the next generation. An mtDNA test can, therefore, be taken by both men and women. The early mtDNA tests looked at a small number of locations in the most variable region of the mitochondrial genome. Today the gold-standard mtDNA test is a full sequence of the entire mitochondrial genome.

The Y-chromosome and mitochondrial DNA are passed on virtually unchanged from father to son and mother to child. They effectively contain a historical record of the DNA, not just from our recent ancestors but from our ancient ancestors on the paternal and maternal lines going back for thousands and thousands of years. Y-DNA and mtDNA tests are, therefore, used not just by family historians but also by anthropologists and population geneticists who are endeavouring to reconstruct the migratory paths of our distant ancestors as they left Africa and spread out to populate the world. Consequently, these tests come with an added bonus as they will not just help with your family history research, but will also provide some insight into your deep ancestry on your direct paternal or maternal line.

The third type of test used by family historians only came onto the market at the end of 2009 and is currently available from just two companies: 23andMe and Family Tree DNA. This test analyses hundreds of thousands of autosomal DNA markers and can help us to explore all the lines on our family tree. We inherit a mixture of autosomal DNA from both our parents, but it is shuffled up and diluted with each new generation, crisscrossing all the branches in our family tree. Although an autosomal DNA test can be used to help with our research on all our family lines, it is most effective for finding relatives within the last five generations or so. In some cases it can help locate relatives within the past five to fifteen generations. These tests can be taken by both men and women.

Uses and limitations

The uses and limitations of each different type of test will be explored in detail in the following chapters of this book, but we will first of all take a look at a few of the basic principles that apply to all of the tests. Firstly, it needs to be made clear that a DNA test is not a magic solution and will not provide you with an instantaneous family history. A DNA test is just one tool which can be used as an aid to research, and it works best when it is used in conjunction with traditional documentary research. If you are lucky you might get a match with someone who is researching the same line as you and who can supplement the information that you already have. A DNA test can also, in some cases, save time and money by providing a narrower focus for your research. If, for example, you have reached a brick wall with your research in London but your surname is found in many different counties, a Y-DNA match with a well-documented line from a specific town or parish will enable you to target your research on one particular county rather than having to scour records across the whole country.

As DNA testing is essentially a match-making game, the success of a DNA test depends on whether or not you get any relevant matches. The chances of getting a match very much depend on who else is in the database. If you test with a long-standing surname project, which has representatives from most of the trees for the surname, you will have a good chance of finding a match. If there is no project for your surname, or the project only has a few members, you might be in for a long wait before you learn anything from your DNA test result. Some of the American-led projects only have participants from the US, and even if you do have a match it will not be particularly meaningful as your match is unlikely to know where in the UK his line originated. The autosomal tests from 23andMe and Family Tree DNA are still both very new and it will take time for the databases to build up in size. DNA testing is, therefore, very much a question of numbers, and the more people who participate the more we will learn. Many people do simply order a DNA test just to add their results to the company’s database and see if they get any matches, but if you wish to have an immediate return on your investment it is better to test within a structured surname project or have a hypothesis in mind and select the appropriate candidates in advance for testing.

One important limitation of DNA testing is that it is very good at confirming that two people are related, but it will never tell us the name of the ancestor we share in common or when he or she lived. You are instead given a range of probabilities as to the timeframe when the common ancestor might have lived. The accuracy of the prediction also depends on the resolution of the test. If two men have identical Y-DNA results with a low-resolution test comparing a small number of markers, the results might indicate that they have a 90 per cent probability of sharing a common ancestor within the last twenty-four generations. A high-resolution test with more markers might perhaps give a 90 per cent probability of sharing a common ancestor within four generations. A 90 per cent probability also means that there is still a 10 per cent chance that the match will fall beyond the expected range.

Who to test?

The choice of who to test is partly decided by the type of test which is being taken. Both men and women can take an autosomal DNA test and a mitochondrial DNA test, but only a man can take a Y-DNA test. If a choice of candidates is available it is always preferable to test the oldest generation, but this is especially important for the autosomal DNA tests, which work within a more limited timeframe. What happens, however, if the person you would like to take a DNA test is no longer alive? People often ask if it is possible to extract DNA from a stamp licked by a deceased relative, a locket of hair, fingernail clippings or other similar items. Sadly, in nearly all cases, the answer is no. In the first place there is the risk of contamination, and there is consequently no absolute guarantee that the DNA is from the required person. Secondly, such testing is expensive as it has to be carried out in a specialist laboratory, and the success rate is low. To extract DNA from hair, the hair shaft is required. Even if any DNA can be extracted, it is highly likely that the pieces of DNA you need will not have survived. There is a greater chance of success in recovering mitochondrial DNA because there is much more mtDNA in each cell, whereas there is only one Y-chromosome, but for genealogy purposes it is usually the Y-DNA which is needed. The other related question which sometimes arises is whether or not it is possible to exhume a body in an attempt to extract DNA. Here the chances of success are even lower as DNA degrades rapidly over time, especially if it has been exposed to the elements. There is also a further hurdle to be overcome as permission is required from the church authorities before any exhumation is allowed, and it is rare for such permission to be granted. In view of all these difficulties, if you are considering getting a DNA test done on a relative it is very important to get the testing done while they are still around to provide the sample.

Choosing a testing company

Once you have decided which test you wish to take, the next stage will be to decide on a testing company. If you are considering taking a Y-DNA test, or getting a relative to test on your behalf, in most cases the choice will be dictated by the testing company hosting the relevant surname project. If there is no pre-existing surname project and you are interested in starting your own project I have looked at some of the issues to consider in Chapter 6. There is more flexibility with a mitochondrial DNA test, but there are many advantages to be gained from testing with a company with a large database which hosts geographical and haplogroup projects in order to maximise the chances of finding a meaningful match. These issues are explored in detail in Chapter 4. The new generation of autosomal DNA tests are reviewed in Chapter 5. The choice of company will very much depend on whether you are more interested in taking the test for health or ancestry purposes. A list of testing companies is provided in Appendix B along with brief descriptions.

Figure 1 A typical DNA test kit consisting of vials of preservative together with some brushes for scraping the cells from inside the cheek. Three samples are usually required.

It is important to remember that the DNA testing market is constantly evolving. Some companies have been at the forefront of the latest developments and continue to introduce new tests and extend their product offerings. In contrast, some of the smaller companies that appeared to be a good choice a few years ago have been taken over or have gone into liquidation. The range of tests offered will be an important consideration. It is not always easy to predict in advance the additional tests that might be required, but if you test with a company which only offers a limited range of tests, if you need to upgrade and the test you need is not offered, it would then be necessary to pay to be retested elsewhere. It is always best to get recommendations from other people who have taken DNA tests and to learn from their experiences. The best way to do this is to make use of the resources, such as mailing lists and forums, listed in Appendix A.

Taking a DNA test

Having decided on a testing company, the actual process of taking a DNA test is very straightforward and simple. There is no need to visit a doctor or have a blood sample taken. The DNA kit is sent out in the post and everything can be done in the comfort of your own home. The kit consists of some small brushes that look rather like mini toothbrushes and a few vials of preservative. The brushes are used to scrape some cells from inside your cheek. It is a completely painless process – the most difficult part is refraining from eating and drinking for at least an hour beforehand! Once the swab has been taken, a plunger is pressed on the brush to release it into the vial. The pots are then sealed up and go back in the post to the testing laboratory. You will usually be asked to provide samples to fill three vials. One testing company, 23andMe, collects DNA in a different way, and requires you to spit into a container. Whichever method is used, once your kit has been received in the lab, it will take anything from four to eight weeks to receive your results. All the major companies will allow you to access your results online and will provide various educational resources to help you to understand your results.

Having discussed the basic principles, we will now move on to explore the different types of test in depth, beginning with the Y-chromosome DNA test and its particular application within surname projects.

2

Surnames and the paternal line

The most popular and widely used DNA test for family history purposes is the Y-chromosome DNA test, colloquially known as a Y-DNA test. The Y-chromosome is passed on from father to son and carries the gene which determines the male sex. Conveniently for the family historian, the path of Y-chromosome transmission usually corresponds with the inheritance of surnames, making the Y-DNA test a very valuable tool as an aid to traditional documentary research. For family history purposes Y-DNA tests are usually co-ordinated within surname projects. Commercial Y-DNA tests first became available in the year 2000. By the end of the decade several hundred thousand men had had their Y-DNA tested, and there were in excess of 6,000 surname projects. Women cannot, of course, take a Y-DNA test as they do not inherit the Y-chromosome. Most women will, however, have a father, brother, uncle or cousin who can take the test in their place.

The Y-chromosome is passed on from father to son virtually unchanged. Indeed when scientists first began to explore the Y-chromosome they found so few differences that it was thought that it would not be very useful for genealogical or evolutionary studies! Gradually, however, as the sequencing technology improved and new techniques were developed, scientists began to spot patterns in the millions of letters that make up the Y-chromosome and discovered that there were particular locations or ‘markers’ which did sometimes change. These markers are known as short tandem repeats (STRs). A number of studies have been published comparing these markers between father and son to establish the rate of change – the mutation rate. It has also been discovered that some markers mutate at a faster rate than others. Once the mutation rates have been established for the various markers it is then possible to infer the relationship between two men purely on the basis of their DNA results and the number of differences between them. Fortunately, we do not have to worry about doing any complicated calculations ourselves. The testing companies do all the maths for us and will provide you with a list of your matches in their database, together with an estimate as to the time when you most probably shared a common ancestor.

Table 1 Y-STR markers, alleles and haplotypes.

A standard Y-DNA test will include a panel of Y-STR markers. When Y-DNA tests first became commercially available in the year 2000, only 10 or 12-marker tests could be purchased. These tests are now considered to be low-resolution tests because a large number of men with many different surnames will have identical results when tested at 10 or 12 markers. As more markers are added to the mix the irrelevant matches start to disappear, leaving only the matches which are of genealogical significance. The standard Y-DNA test today uses at least 37 or 43 markers. Some companies offer the option to test additional panels of markers which can bring the total number of markers tested up to over 100. A Y-DNA test result is received in the form of a string of numbers representing the values for each of the markers tested. On its own this string of numbers is essentially meaningless. The value of the test comes when you start to compare your numbers with other people and, in particular, with men who share the same surname. Close relations, such as father and son, uncle and nephew and first and second cousins, will in most cases match each other on 37 out of 37 markers. This is known as a 37/37 match. In other words, they will have an identical set of numbers on all 37 markers. The further back in time you go the greater the chance of finding a mutation. Two third cousins might, therefore, match on 36/37 markers. Two sixth cousins might match on 35/37 markers. The more matching markers the two men share the more closely related they will be. If they mismatch on too many markers they will not share a common patrilineal ancestor within a genealogical timeframe, or in other words in the 900 or so years since surnames began to be introduced. A DNA test is, therefore, a very effective tool to determine whether or not two people with the same surname are related, but it will not give you the name of the common ancestor or tell you when that ancestor might have lived. The names and dates can only be determined by traditional documentary research.

Surname projects

A Y-DNA test is best taken within a structured surname project and the value of the test will grow over time as more people join the project and a picture of the surname’s distribution and origins begins to emerge. The Y-DNA test can be used within a surname project in a number of ways. Firstly, it can be used to verify the existing documentary research. With the increasing availability of online records such as civil registration indexes and census records, it is generally a reasonably straight-forward matter to trace a British line back to the beginning of the nineteenth century. However, as you go further back in time through the parish registers the links between each generation become less conclusive, especially if no other supporting evidence can be found such as a will or an obituary. You might, therefore, find a baptism record in one parish which matches the age given in a burial record in a neighbouring parish. With a rare surname it is usually safe to conclude that you have found the right baptism but it is often easy to make false assumptions, especially if the parish registers for the neighbouring parishes are not readily available online. A Y-DNA test, therefore, provides the opportunity to check the validity of your research, providing that the appropriate candidates for testing can be found.

Figure 2 A certificate showing the results of a 67-marker Y-DNA test from the author’s father.

A Y-DNA test can also be used within a surname project to test a particular hypothesis, such as whether or not two lines are related. It is often the case that two people will be researching the same surname but are unable to find any link in the paper trail – one line might trace back to the 1600s in Devon and another line might be stuck in the 1700s just across the county border in Somerset. If a male descendant from each line takes a Y-DNA test it will be possible to establish once and for all whether or not the two lines are related on the paternal line. A match will provide conclusive proof of the hypothesis, but the lack of a match does not rule out the possibility that the two men are related on a female line. If the lines do not match, it is advisable to test a second candidate from each line so that the lines can be verified back to the earliest possible date, thus ruling out the possibility of a break in the link between the Y-chromosome and the surname in more recent times.

Figure 3 A display of Y-DNA results from the Cruwys project. The men with matching or closely matching results are grouped together.

Most surname projects will want to test people from as many different trees as possible to see which lines are related. As projects grow in size the chances of finding a match within the surname project will greatly increase. My own Cruwys/Cruse DNA Project now has almost sixty project members. Although I still have quite a few singletons awaiting matches, many of the other results are beginning to cluster together into distinct genetic families. I have often been surprised at the lines which do match. Other lines which I was convinced were related turned out to be not connected at all!

In the early days of a surname project the focus will probably be on locating a single representative of each documented line to participate in the project. In the long run it is advisable to test at least two people from each line to verify the tree back to the point where the men share a common ancestor. If you have successfully documented a tree back to the 1600s or earlier, it is advisable to test descendants from as many of the different branches as possible. If enough people are tested from each branch it is sometimes possible to identify, by a process of elimination, specific mutations which are unique to a particular branch. Mutations do, however, occur at random and there is unfortunately no guarantee that a crucial branch-defining mutation will occur where it will be of most use! Family trees also come in all shapes and sizes, and some are more reproductively successful than others. Often one branch will flourish and have multiple living descendants, whereas other branches have become extinct or might only have a handful of living descendants. It then becomes a matter of priority to trace those descendants and persuade them to share their DNA.

All projects will have a number of lines which are stuck in more recent times. London research is particularly problematic, especially if your ancestor unhelpfully died before the 1851 census and, therefore, left no indication as to his place of birth. The 1841 census does at least provide the birth county, but it can still be quite a difficult task narrowing the search down to a particular parish within that county. The ancestor who gives his place of birth in 1841 as Scotland or Ireland presents even more of a challenge, especially if he has a particularly common surname! It can also be difficult researching emigrant lines, especially to Canada and the US where civil registration started very late, and in many cases not until the early 1900s. Although census records are available they do not provide sufficient information on the place of origin to be useful to the family historian, and it is only usually the birth country which is recorded. DNA testing can be a very useful tool in such scenarios. The chances of success depend very much on the size of the surname project and the range of lines tested, but if there is a match with a well-documented line originating in a particular town or village, your research will have much more focus and there will be a much greater chance of finding the link in the paper trail.