Trowbridge Family Y-DNA

The American Trowbridge family traces its origins to a manor in Devonshire, in the parish of Crediton. The Trowbridge House was the property of Peter de Trobrigge (c.1272) in the reign of Edward I, and remained in the Trowbridge family until it was sold around 1720. The ancestry of Peter, however, is unknown. Did he derive his surname from a prior residence at the town of Trowbridge in Wiltshire? Or did he have another, independent source for his surname? Y-DNA may provide some clues.

A few years ago, I donated a sample of my DNA to an organization called the Sorenson Molecular Genealogy Foundation. At the time, they were offering to do a free 17-marker Y-DNA test, provided that I also submitted a copy of my male-line pedigree, with the understanding that the results would be included in their massive genealogical database.

As a sidebar, let me address what I anticipate to be your first two questions:

a)  It’s not a full genetic profile, and even if it were, the FBI won’t be getting a copy, and
b)  The “sample” was in the form of a mouth-swab.  Get your mind out of the gutter!

For those who aren’t familiar with Y-DNA and it’s importance to genealogy...  I’m sure you all know that males have a X and Y chromosome, and that all male children inherit the Y chromosome from their father.  The chromosome passes from father to son basically unchanged, save for small random mutations that occur on average every six generations or so.  This means that my Y-DNA profile is identical (or extremely similar) to my father’s, and to his father’s, and so on... all the way back to our earliest known Trowbridge ancestor.  And all male Trowbridges descended from the same ancestor, no matter how distantly, would have the same profile.  Thus by examining the Y-DNA we can determine if any two male Trowbridges indeed share the same ancestry, or if they are two completely unrelated families that happen to use the same surname.  We can also see if two families with different surnames might be likely to share a common ancestry hundreds (or even thousands) of years ago.

Since the SMGF did not send results directly to the participants, I promptly forgot about my submission until I discovered their website years later.  It turns out that Y-DNA from four Trowbridges are in the database:  Three of them (including me) are all descended from William Trowbridge (1633-1690), one of the three sons of Thomas Trowbridge the immigrant; and of those three, two of them (including me) are descended from Samuel Trowbridge (1797-1867) of Kendallville, Indiana.  The other Trowbridge lives in Yorkshire, England.  Also, the other three participants all had a more comprehensive 43-marker test.

The results show that, as expected, I am a match to the other two descendants of William Trowbridge.  In fact, I am an identical match to the one who is NOT descended from the Kendallville Trowbridges. The other one matches 16 of 17 markers, so his line apparently had a single mutation within the past five generations. (The mutations are actually helpful from a genealogical perspective, because they allow us to uniquely identify a specific branch of the family.)

As far as the Trowbridge who is living in Yorkshire, England... not a match.  Not even close.  This could mean that his paternal line includes an adoption, thus the genetic line is broken; OR it could mean that, when surnames first became common around the 15th century, many unrelated families in England independently began using “Trowbridge” as a surname.

Here’s what the results look like:


Line #2 is mine. Line #3 is a descendant of Ira Benjamin Trowbridge (who, like me, is a descendant of Samuel Trowbridge of Kendallville). Line #1 is a descendant of Sylvester Trowbridge of Missouri. Line #4 is the Trowbridge from Yorkshire.

The full profile is more easily seen in the table below, with the non-matching alleles (i.e., mutations) marked with asterisks:





We can learn various things about the origins of our Trowbridge family simply by examining the DNA itself, as every DNA profile falls into a “haplogroup” which shows the racial and geographical origins of the paternal ancestors.  Our haplogroup is I-M170, subgroup I1-M253.  The extended modal haplotype most closely matches I1a-uN, also known as "ultra-Norse." Thus surprisingly, despite the fact that our line came out of England, our Trowbridge ancestors were not natively Anglo-Saxon, Norman or Celtic.  Rather, our haplogroup has its origins in the northern regions of Scandinavia, and even today the vast majority of people in our group are Norwegian.  That's right, folks... we're Vikings! See the resemblance?

The SMGF database can also be accessed via a site called GeneTree, which permits you to manually enter your Y-DNA profile (or mt-DNA, for you females who are feeling excluded and want to trace your maternal heritage), if already known. [Update: GeneTree is no longer active. Sucks to be us. :-( ] I took the liberty of creating a profile for William Trowbridge (b.1633), which can then be used as a search template to find closely matching profiles. Sadly, it seems there aren't many Norwegian participants in the database, but we do find some Scandinavian connections with names such as Palonen (Finland), Abrahamsson (Sweden) and Arnason (Iceland). Other close matches have the surnames Prindeville (Ireland), Hicks (New York), Stevens (England) and Shaftoe (England). All of the above profiles have markers matching at 92% or better, which suggests a 50% probability of a common paternal ancestor within twenty generations.

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