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Chromosome Mapping Opinion

Am I actually a Dutchman?

AncestryDNA have just launched their latest ancestral populations update. One of the changes I can see is that I’m now considered to be 7% Dutch. I could just smile about this and ponder whether it influenced me moving to Amsterdam as young man. But since AncestryDNA have also updated their Chromosome Painter, I can also analyze it in a bit more detail.

AncestryDNA Chromosome Painter

The AncestryDNA chromosome painter launched in the summer of 2022. One issue at launch was that it often reported different populations as entire chromosomes, which didn’t seem to make sense. At first glance, it looks as if this might have improved slightly with the new update, but I still see some odd ‘whole chromosome’ segments such as the Icelandic one on chromosome 9.

My updated AncestryDNA chromosome painter results from October 2024
My updated AncestryDNA chromosome painter results from October 2024

Assessing these segments at AncestryDNA

Via their SideView technology, I can check at Ancestry whether these Dutch segments are maternal or paternal. Clicking Maternal and Paternal above the chart indicates that

  • The whole of my maternal chromosome 11 is considered Dutch
  • The other four Dutch segments on chromosomes 3, 10, 16 and 22 are paternal.

I’m feeling sceptical at this point, but I’ll carry on!

Exporting the Dutch segments

While Ancestry just provides the chart above, I can use a tool at DNA Painter to obtain estimated start and stop positions for each segment. For more background on the Ancestry Chromosome Painter segments tool, you can read my previous blog post.

After pasting the contents of the chromosome painter page into my tool, I click Create new chromosome map and am taken to a DNA Painter version of the AncestryDNA chromosome painter.
(You can also just download a spreadsheet with the segment positions)

My AncestryDNA chromosome painter segments imported into DNA Painter
My AncestryDNA chromosome painter segments imported into DNA Painter

Each population now appears as a different match, which I can then overlay on my chromosome map to see if it provides any clues as to the origin. I also have the previous iteration of my chromosome painter output for reference.

I can get just this data by clicking on any pink Netherlands match and clicking View match.

The segment popup that appears when I click on a Netherlands segment
The segment popup that appears when I click on a Netherlands segment

This then brings up the match overlay where I can click copy match segment data to clipboard.

The match detail overlay for the match The Netherlands in my chromosome map
The match detail overlay for the match The Netherlands in my chromosome map

I can then switch to my main chromosome map. There, I can click Paint a new match, paste in the segments I’ve copied to the clipboard, and then click Preview to overlay them on my map.

I can then consider each segment in turn.

Chromosome 3

This aligns with the whole of an ancestral segment I inherited from my English grandmother that I’ve been able to determine via visual phasing and comparison with my paternal half-uncle.

The "Dutch" segment (the black and white one at the top) overlaid on my paternal chromosome 3
The “Dutch” segment (the black and white one at the top) overlaid on my paternal chromosome 3

What I knew about this segment before

Based on another cousin match, the left-most portion was inherited from her grandfather Charles Richard Jones. Prior to this update, AncestryDNA classified this segment as England & Northwestern Europe.

What I’ve learned

Not much, except that it seems AncestryDNA’s algorithm is now categorising this entire segment as Dutch. Does that mean the whole segment might have been from my Jones line? Perhaps!

Chromosome 10

Again, the “Dutch” segment aligns with almost all of an ancestral segment from my English grandmother.

The "Dutch" segment (the black and white one at the top) overlaid on my paternal chromosome 10
The “Dutch” segment (the black and white one at the top) overlaid on my paternal chromosome 10

What I knew about this segment before

Based on other matches, the right-most part is from her paternal Jones side. I had provisionally assigned the left part to her mother. Prior to this update, AncestryDNA classified this segment as Scotland.

What I’ve learned

Again, not much, but perhaps this means my assignment on the left is wrong? It’s obviously hard to know how much to read into the AncestryDNA population segment.

Chromosome 11

This one makes no sense at all!

The "Dutch" segment (the black and white one at the top) overlaid on my maternal chromosome 11
The “Dutch” segment (the black and white one at the top) overlaid on my maternal chromosome 11

What I knew about this segment before

My maternal chromosome 11 starts with DNA from my maternal grandmother. I then have a crossover with DNA from my maternal grandfather, and then another back to my maternal grandmother. As ‘Scotch Irish’, most likely have unknown ancestors from Scotland and England. Prior to this update, AncestryDNA classified this segment as Scotland.

What I’ve learned

It’s hard to see this as anything other than AncestryDNA’s algorithm mistakenly identifying this as Dutch.

Chromosome 16

As on the other paternal chromosomes, the “Dutch” segment is associated with my paternal grandmother. But this time it seems to span two ancestral segments.

The "Dutch" segment (the black and white one at the top) overlaid on my paternal chromosome 16
The “Dutch” segment (the black and white one at the top) overlaid on my paternal chromosome 16

What I knew about this segment before

I have been able to assign most of the blue segment to my grandmother’s Jones grandfather. The yellow segment at the end is one assigned to my Jewish grandfather at the end via an 11cM match with my dad’s paternal half-brother. Prior to this update, AncestryDNA classified this segment as England & Northwestern Europe.

What I’ve learned

It’s possible the yellow segment is a false positive:

  • Unlike many of my “Jewish” segments, I don’t match other obviously Jewish people here
  • Neither 23andMe nor AncestryDNA (this iteration or the previous) identified it as Jewish

Chromosome 22

Same story as the other paternal segments.

The “Dutch” segment (the black and white one at the top) overlaid on my paternal chromosome 22

What I knew about this segment before

Not much, just that the entire tested portion of the chromosome is from my paternal grandmother. Prior to this update, AncestryDNA classified this segment as England & Northwestern Europe.

What I’ve learned

Not much!

Conclusion

On the positive side, this has made me look at a segment assignment on chromosome 16 and conclude that it’s probably wrong.

Beyond that, it all feels a bit speculative:

  • Perhaps all these segments are from a specific Jones branch of my tree, and in the future, I’ll figure out a big Dutch connection.
  • But it feels more likely that they’ll be gone in the next big AncestryDNA update

I’ll report back next year. In the meantime, I’m just a guy in Wales who speaks some Dutch quite badly!

Further reading

Contact info: @dnapainter.bsky.social / jonny@dnapainter.com