DEPARTMENT OF GENETICS - Prof Mark A. Jobling

BritishIslesDNA

Surnames, Genes and the History of Britain

Surnames and genetic structure: a molecular analysis using Y-chromosomal DNA polymorphisms

Frequently asked questions


This frequently asked questions page currently features answers to the most common questions that may be posed after receiving your information; this page will be updated to answer any further queries that may arise regarding the results that we have provided.

How can I find out about other participants who share my surname?

Because of the strictures of the Data Protection Acts, we cannot divulge personal information about any participant in our study to any other. However, after contacting participants we provided an online facility whereby participants could contact each other if they so wished, and, for example, find out whether there were participants sharing their surname, and maybe also their Y chromosome type. This facility is now closed.

How can I use my Y-STR haplotype to search the Y-STR Haplogroup Reference Database?

The excellent Y-STR HRD contains information on many thousands of men's Y-STR haplotypes in many worldwide populations. By entering your haplotype into the search facility of this database it is possible to find the geographical distribution of individuals with matching haplotypes. Below is a screenshot from the Y-STR search page, which is where you enter your haplotype, using the scroll-down menus to choose the number of repeats at each STR, as listed on the sheet that we sent you. Note that the database does not contain information about haplogroups, nor about all of the Y-STRs we typed: you can enter repeat numbers only for the nine markers DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS438 and DYS439.

Screenshot from YSTR HRD Search page

After entering your haplotype, press the search button and a map will appear that shows you the geographical distribution of men whose haplotypes match yours. If you get no 'hits', you could try removing DYS438 and DYS439 from the search. Note that the Y-STR database does not provide any way for individuals with matching haplotypes to contact one another, and that surname information is not available for the males whose Y chromosomes are in the database. If the database search facility is not working properly, please do not contact us, but the database curators, who are listed on their website.

Where can I learn more about Y-STRs?

Visit the NIST webpage, which has excellent up-to-date material.

If two men share the same Y-STR haplotype, do they necessarily share the same haplogroup?

Not always, but given the number of number of Y-STRs (17) we have typed, an identical haplotype will normally imply a shared haplogroup.

If two men are in different haplogroups, is it possible for them to share a Y-STR haplotype?

Yes, but this would normally only be between closely related haplogroups within the Y chromosome tree.

If two men share a Y-STR haplotype and are in the same haplogroup how long ago did their common ancestor live?

A difficult question. Technically, for 20 Y-STRs, the most probable time is 9 generations ago, but the likely range is 0 - 46 generations ago, so there is a lot of uncertainty (the uncertainty is greater for the 17 Y-STRs we typed). To get more reasonable certainty we would need to type a lot more markers; over 200 are now available, so in principle the uncertainty could be reduced greatly, but at prohibitive cost. Interested readers are referred to Bruce Walsh's page on the Family Tree DNA website.

What if there is a difference at only one Y-STR?

It increases the time to most recent common ancestor; this issue is addressed at the same site as that above.

My Y-STR haplotype does not contain all 17 markers - why not?

A few of the many DNA samples we prepared were not of very high quality and in these cases some of the markers were difficult to type.

I belong to a haplogroup (A, BC, H or K*) that is not discussed as a European haplogroup in the sheet I received - what does this mean?

A few individuals within the study belonged to rarer haplogroups that we did not include in our European discussion. Some of these are non-European haplogroups that reflect relatively recent immigration to Europe from other parts of the world. Some others are rare European lineages for which there is as yet little published information.

Why were the haplogroups in this study not defined at higher resolution?

Ideally, we would have liked to define haplogroups at higher resolution than we did (for example, subdividing haplogroup DE into D, E3a, E3b etc.), but we had to make pragmatic decisions based on the cost of carrying out experiments, the time available to do them, and the resolution sufficient to address the study's questions.

What can I actually learn from my results?

As as an individual, you can visit the Y-STR HRD and look at the geographical locations worldwide of men bearing Y chromosomes similar to yours. You could use the internet to seek genealogists who are already conducting a genetic genealogy project on your name – you may be able to use your results from our study to take part. Click here for links to examples of existing DNA-genealogy projects. If you are part of one of our in-depth surname studies, we will be publishing the results later and summarising them here, and you will learn more about the relationship of your Y chromosome with those of other men who share your surname.

I was asked some questions about whether I use my left or right hand for various tasks - what was the result of this study?

We asked these questions because there is some evidence that a gene related to handedness lies on the X chromosome, and that there is a related gene on the Y chromosome. If this were true, then we might find that there was a non-random association between Y haplogroup and handedness, due to functional variation in the Y-linked gene. So far, our analysis indicates that there is no such association; however, this not disprove the existence of a Y-linked handedness gene.

How can you be sure that the tests you do are of no medical relevance?

To the best of our knowledge, we selected markers that gave no information about the health or physical status of our volunteers. However, since the project began, new information became available that means that one of the binary markers, PN25, can signal possible information, through its occasional absence, about fertility status. We have found three cases (~0.1% of sample) where PN25 is absent, which could indicate fertility problems. We have described this phenomenon in a paper that has recently been published, in order to draw attention to the potential problem for other genotyping projects (see the Journal of Medical Genetics).

We (like others) did not consider the PN25-infertility connection until we found deleted individuals, so our initial assurance that markers were not of medical significance was given in good faith. Had all the current information been available at the time of choosing markers, we would certainly have made different choices. However, since there are now other markers available to define the haplogroups (and, in particular, hg R1b3), it is perfectly possible to return honest haplogroup information to all participants. In retrospect we realise that there is a lesson for geneticists in that we need to remember that no marker can be considered strictly neutral.

Our major cautionary point about typing is for microsatellites, in particular DYS464 (which was not typed in our study, but is typed by some commercial companies). These are not haplogroup-defining markers, so must be reported individually, and absence (or a ‘null’ allele) may imply infertility.

With regard to the three individuals (~0.1% of the sample) in whom we have identified deletions, we do not intend to inform them of their deletion status: deletion testing was not the purpose of the study, and was not the reason that participants volunteered in the first place; furthermore, there is more than one case in the literature of men with deletions of this region who have fathered children – in other words, detection of a deletion does not represent a simple predictive test of fertility status. Finally, this information is kept strictly confidential and would under no circumstances be revealed to any third party.

How can I get further analysis done on my Y chromosome?

We have carried out our analysis purely for research purposes, and for free. If you want further analysis done, and have some spare cash, you can contact any of a growing number of commercial companies that offer these services. We have no connections with any of these outfits, so make no particular recommendations. To find a company, search the internet using the terms 'DNA' and 'genealogy' and maybe 'Y chromosome'; you will find plenty, and you may also find useful advice from genealogy discussion groups about the pros and cons of different companies. Good luck!

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Last updated: 3rd August, 2006
Mark Jobling
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