A Y DNA Cousin in Medieval Denmark

R-ZP121 in Tjærby Denmark Circa 1100-1300 CE.

First off, I want to acknowledge the cover photo I’ve stolen from Google Maps, which was taken by Niels Blumensaat. The location for this DNA find is a small town just outside of Randers, Denmark. The samples are from an abandoned medieval graveyard used in a bone growth study comparing rural people in Tjærby, Denmark, to urban people in Randers in the Middle Ages. I couldn’t find a lot of pictures of the place. There were pictures of Dronningborg a few kilometers away, so I have lovingly borrowed one of those.

Tjærby Denmark google map town level resolution

It took me a while to find the studies that our man from Tjærby is associated with. I ended up with two. The first one was the bone growth study I mentioned above, and the second was a study on Genetic risk for Multiple Sclerosis and Steppe Pastoralist populations. I believe it is the second study that FTDNA is citing. The supplementary material has our guy, Tjærby 750, also known as KHM899 A692/X173 or CGG100750 number 4. In the data KHM899 and CGG100750 seem to be more locational, a dig location on a site with multiple remains. A692/X173 seems like a more definitive identifier.

Tjærby Denmark in Jutland Denmark.

Without Family Tree DNA ancient connections, I probably would not have seen this guy and I would not have known that their Y DNA was tracked down to R-ZP121 under CTS12023. I have to give the M.S. study a bunch of credit for having the Y DNA down to R-Z18->CTS12023 figured out, though. It wasn’t that long ago that we would not have any resolution beyond R-U106.

Looking up Tjærby landed me on a Danish website with an English translation. I can’t vouch for the accuracy, but it translated into “Tar Town”. I know that some Viking age settlements in Britain have modern names ending in “by” so it seems plausible. Why it is Tar Town, I do not know.

The Family Time Tree

There are 74 of us (at the moment) under R-ZP121 with eight recognized branches (according to FTDNA). Our man from Tjærby could be down any of those or completely on their own branch. I’m spoiled to have this much resolution on Y DNA for our small group, but our common ancestor in R-ZP121 is estimated to have lived in 200 CE. That’s roughly a thousand years before our cousin in the Middle Ages. He’s certainly on a branch with that many generations under his belt.

What we have is…sort of, a set of bookends for R-ZP121 and the migration period/Viking age. We’re spoiled to have that as well at this point. Two ancient samples at this resolution are pretty amazing. It’s good to keep in mind that ZP121 is itself a collection of SNPs. A straight line of father-to-son relationships with no branches for at least 14 generations. There are a lot of unknowns there. Then, below that, we have eight known branches.

I’ll use my own tree as an example of when our cousin falls within the family.

ZP121 time tree including Tjaerby 750 and the branches down to my own home branch A2284.

Alright, borrowing FTDNA’s time tree you can see my branch of the Elmer/Elmore family down on the right in red. I’m down the R-A2284 branch, which we’ve triangulated to Edward Elmer 2, who was born in 1654. One step back is Ed Elmer, who was born around 1610 or so in A2276. The time tree has done a pretty good job of estimating those age ranges.

Then you jump back to ZP129 when our family splits from the Knowltons circa 900 CE give or take a few hundred years. Tjærby 750 is younger than that estimate, coming in around 1100 CE, but could be about the same time. He’s after the Norman invasion of England, though.

My next hop is ZP124 when our family splits from the Lunceford family. On the time tree, you can see that it roughly lines up with Hatherdene 5, our Angle from the Wash, who was born around 400 – 600 CE. He’s the other bookend for ZP121. He’s about 200 years from the source ancestor and likely on a branch below ZP121.

The next hop is BY41998. This one is a single SNP. One single ancestor, born around 250 CE, give or take a few hundred years. This is where my family split from the Wright, De Burchgraeve, Stanuczek, and Winne families. There is also a third line, but I’m unsure what family is at the end of it. They have one branch estimated to be around 1200 CE. We’re all definitely descended from Mr BY41998, and even though it is unlikely, any of us could be more directly related to Hatherdene 5.

One more hop back in time, and there are seven other branches under R-ZP121. Any of those branches could be more directly related to Hatherdene 5 or Tjærby 750.

Between our human bookends, Hatherdene 5 and Tjærby 750, is a big chunk of the migration period and the Viking age. I have gotten to the point where I think of it as a spaghetti mess of moving people that Hatherdene 5 was a part of and that Tjærby 750 might be a product of.

Bookends in Time but Maybe from the Same Space?

Branches that cover or form within this time frame, under ZP121, contain modern men from Poland, Germany, France, Belgium, Netherlands, England, Ireland, Wales, Finland, and Sweden (with a chunk of men also in “unknown” or United States). That makes the location of these two ancient DNA samples interesting as well.

They’re both ZP121. They cover a large portion of the time when all of the migration period action occurs. They’re 800 years apart, but in theory, they’re both from the Jutland Peninsula. Hatherdene 5 was not admixed. He was a continental northern European. His autosomal DNA didn’t suggest any time spent among the Franks before heading for Britain. We could hypothesize that he left Angeln or his parents both did. In some theories, the Angles and Jutes migrated down the coast and to England because of the encroaching Danes from the east. Tjærby 750 lived and died on the Jutland Peninsula. Perhaps his family never left. Maybe they just became Danes.

There are biases in testing, limits on the depth of testing, and limits on the amount of material that CAN be tested. These limiting factors can converge to cloud the real paths we’ve taken. My bias towards southern Scandinavia and Jutland, particularly as a reservoir for CTS12023, is pretty obvious to anyone who has read my diary here.

It’s easy to fall into confirmation bias because I feel like I’ve been watching this pattern unfold for a decade or more.

With that in mind, this is what is actually being presented as evidence. I don’t have to do a lot of backbends, and yoga stretches to make this fit. Ancient ZP121 is found in the Jutland Peninsula and places and cultures associated with migration from the Jutland Peninsula. If we’re lucky, there will be more evidence in the future that fills in more locations and gaps in the timeline.


  1. Very informative mike, Once again a great post… Just two questions, am I right in assuming That Heatherdean 5 Possibly migrated from The Jutland peninsula, And lastly the other samples in buckland close. That are positive for DF95 Do you think They Came as a family and are related to Heatherdean 5…. Thanks once again and I wish you and your family a merry christmas and a safe new year.

    • Thanks Chris. I believe the Buckland samples were from multiple families but I’d have to look back at my notes on that. It seemed like they were somewhat unrelated or distantly related. Hatherdene had a younger female relative with him. My memory is awful but it seemed like there was a variety of admixture in Kent suggesting a layover where the families picked up some Iron Age French DNA. The anglo saxon study represented that as a move through the continent, which makes sense. What is interesting to me is that Hengist shows up in the Finnesburg fragment. Hengist and Horsa famously settle near and found Kent. Finnesburg is apparently in Frisia (or what was then Frisia). Hengist might have been a popular name so who could say it’s the same guy, but it is interesting that there are some literary references to Jutes in Frisia and then Jutes a bit farther south in Kent where there are a cluster of DF95 men attributed as Jutes. Kent was a swirl of different people as far as the study was concerned. Hatherdene 5 didn’t have any appreciable admixture so I don’t think there is a good reason to float him down through the continent to get to the wash. As far as Kent, my bias is that water wasn’t a barrier to these people so the land route seems a lot harder to me than bouncing down the coast and settling along the way and then infiltrating the continent. I’m thinking of Denmark as some sort of weird lawn sprinkler.

      • I recently had some concerns about the depth of Y DNA analysis in genomic studies. There are degraded samples, but also lack of knowledge. Many of the men in the anglo saxon study in Kent may be on unknown lines of DF95. I think they may be finding ZP121 because they’re looking for it. Yleaf which is used by multiple studies uses the Yfull tree. https://www.yfull.com/arch-3.16/tree/R-DF95/ you can see that ZP121 is the only group below DF95 in this old tree. So if the version of the tree they’re using for yleaf in a study is old, then you’d be ZP121 or set back to CTS12023/DF95 where a more updated tree would give more granular results: https://www.yfull.com/tree/R-DF95/ Because you have to pay to enter your results into YFull, there is another barrier to having your Y haplogroup show up in these genome studies. Yfull also, at least when I entered results, downgrades your test to big Y 500 coverage. So some SNPs will fall outside of their coverage area. I’m splitting hairs of course. These genomic studies are only incidentally looking at YDNA, we’re lucky to have any resolution at all, but I worry about some gaps in the trees underlying the research.

      • glancing over my notes on the Buckland samples, overall the groups from Kent were very diverse with DNA from the British isles and continental northern europe along with iron age french. Quickly looking at https://wanderingtrees.com/2022/09/30/its-my-swamp-anglo-saxon-df95-follow-up/ It seems like the DF95 men are unrelated or distantly related, but some of them have family groups with a range of admixture. The DF95 men I had marked out seemed to have lower admixture from Iron Age French sources, but some of the members in the family had higher admixture. That is what makes me speculate about one group up near cambridge that packed up and moved so you have newbies and their admixture is with the locals in Britain and then another group that hopped down coast or spent some time on the continent before moving to Britain, like a two stage migration rather than a straight shot. Our Y DNA happens to be in both groups and I think evidence points to both groups starting up in continental northern europe.

        Our Y DNA is kind of a lagging indicator because autosomal DNA changes with every couple. As an example, If I moved to France and found a spouse, my grandkids would probably be french with a high incidence of French admixture, my contribution to their autosomal DNA will shrink every generation, but their Y DNA haplogroup R-A2284 formed in North America in the 1600s. No matter how continental european they become their Y DNA is still North American Y DNA for several hundred years. If my cousin Tim’s grandkids who live in North America move to France as well with their entire families, their admixture will be pretty different from my grandkids in the same time frame with the same source Y DNA. If he moved with his whole community it could take a while for them to become admixed French citizens because they will likely intermarry, while my bachelorhood set up a different chain of events.

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