Skip to content

The S-NN-TT genealogical DNA study

DNA surname studies can have enormous potential to help break down brick walls of conventional document-based genealogy.  In the case of the S-NN-TT worldwide surname study, there are now a really big number of variant spellings with just about any combination of vowels in the gaps between S, NN, and TT, and even some versions with a single N or T, or an additional E on the end.   Although it can be relatively easy to follow through families from about the 1830’s and be fairly sure of the family links from things like census and birth, marriage and death documents, it starts to get much more difficult as you go back further and spelling becomes less consistent, or parish records less detailed.  This means that there comes a point in most family trees where even if you think two or more families are related, there just isn’t the cold hard evidence for it.

That’s where genetic DNA studies really become useful.   Y-DNA in particular gets handed down virtually unchanged from father to son through the generations.   That means that by testing the Y-DNA of a living male, who has a well documented ancestral line back to the earliest known ancestor in that line, then you are able to get the y-DNA “signature” for that whole line.   If you test another male from a completely separate line, and their DNA signature matches the first one very closely, then that makes it highly likely that there is a shared ancestor, and those two trees are linked a generation or more further back.

That means that if you have a number of different family trees of people using the same or very similar surname,  then you can use DNA studies to see which groups have common ancestors, and should be linked.    In our case, some of the potential links that may be proved or disproved by a DNA study  for the Sennett name and all its variants are:

– seeing whether any of the many Sennett/Sinnott/Sinnett/Synnett families worldwide that can trace origins back to Ireland, and particularly Co. Wicklow or Co. Wexford  can be linked.   This includes the currently unlinked family groups in Durham, Birmingham, Lancashire, Yorkshire and other places in England; Prince Edward Island and other areas of Canada; Maine, Ohio, Illinois and other areas of the US; and also Australia and New Zealand.


– identifying whether there is a link between Welsh Sinnett’s and Irish Sinnott/Synnott’s, given that some of the Co Wexford Sinnotts had Flemish origins, and there is documentary evidence that these Flemish people came to Ireland after first living in Pembrokeshire, Wales.

–  checking to see if there is any link between the Cornish Sennett’s and the Co Wicklow, Ireland, Sinnott’s – given that many of the Wicklow Sinnotts were miners, and Cornish Mining Companies were operating in Co Wicklow.

– seeing whether the Sennitt ancestral group, which have been very well documented right back to the 1500’s in Cambridgeshire,  have any connection at all to any other group with a similar name – especially earlier groups in London (who also don’t seem to link easily to any of the other family groups identified).

– proving or disproving the suggestion of a potential link between Cambridgeshire and Cornwall where it isn’t known who first suggested this link (that Jeptha Sennett may possibly have come from Cambridgeshire), or what their evidence for it was.

The Sennett DNA study link is here:

Although anyone (male or female) can take a genetic DNA test and sign up to the Sennett Study,  the study particularly needs at least one Y-DNA 37 marker test from each known and documented family group, and  Y-DNA tests can only be done by males.   Anyone purchasing a test kit and signing up to the Sennett DNA study is also then free to join any other projects they may be interested in at no extra cost.  If you do sign up to the Sennett Surname Project, then you will also need to supply a copy of your direct line ancestry to me, as without that, it will be impossible to make sense of the results.

So, please spread the word,and club together to encourage at least one member of your extended family to take a test.   If you already have a near relative who has been tested but want to support the project, then a donation to the general fund (through the familytreeDNA project website) will allow the project to sponsor testing of other family lines that will provide valuable information to identify which groups are linked genetically.



Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

%d bloggers like this: