More Lentz/Nicholson DNA and the 1st Cousin, 2nd Cousin Combo Rule

A little over a year ago I decided to test my autosomal DNA at 23andme. I had tried the other 2 testing companies and was curious as to what 23andme was like. Perhaps I would have some more matches that I didn’t know about. The most interesting match that I found was my mother’s 1st cousin once removed. Her name is Judy. I was asked  her if she would  upload her results to gedmatch.com for analysis. She tried a few times without success. Recently, she went back and successfully uploaded her results, so now I can write about them.

Lentz/Nicholson Lines

Judy descends from our common Lentz/Nicholson Line. Others that I have been in touch with and have tested for DNA are just from the Nicholson Line. The Nicholson Line is in red. The Lentz line is in yellow. The Lentz/Nicholson Line is in orange. From my early school days, I recall that if you mix yellow and red, you get orange. Judy and Joshua are on the orange line. My mom shows as green, but for the purposes of this Blog, can be considered orange also.

lentznicholschart

The bottom row indicates people that have had their DNA tested. There is also a further out line of Nicholsons that I don’t have included here.

I haven’t identified anyone yet who is only from the Lentz Line.

Here is Judy’s match with my mom at Gedmatch:

judymomgedmatch

comparing cM’s for first cousin once removed

Their total match of 269 cM is actually on the low side for 1C, 1R. Here is a Bettinger study showing the average DNA shared between 1st cousins, once removed as being in the 400 cM range:

bettinger1c1r

Not to be outdone by Blaine Bettinger, I also looked at some of my own family relationships to see how they compare:

joelcmstudy

So with just 8 people, I came to the same conclusion on the average amount of DNA that 1st cousins, once removed shared. Blaine took thousands of people to come to his result. Another side point of interest is that my brother Jon shares over 150 cM more with my dad’s first cousin (583.7 cM) compared to what my sister Sharon shares with my dad’s first cousin (421 cM).

Chromosome Mapping for Mom

Judy’s new DNA results update my mom’s Chromosome map in many of the red areas below:

momchromomapoct16

More About Judy’s DNA

Based on the tree, we can see a few things.

lentznicholschart

  1. If Judy matches Joan or Carol, that means the DNA has to be from the Nicholson side.
  2. If she matches my mom and no red people, then the DNA could be from Lentz or Nicholson.
  3. If Judy matches just Joshua, the DNA could be from Lentz, Nicholson or from the wife of William Lentz.
  4. If she matches my mom plus Joan or Carol, the match would be from the Nicholson side. If Judy matches Joshua plus Joan or Carol, the same should apply. However, this would have to be a triangulation group.
Judy’s Nicholson (or Ellis) DNA

William Nicholson

Here is an example of Judy’s Nicholson DNA. She matches both Carol and Joan who are not descended from the Lentz family.

judynicholson-match

These 3 are also in a triangulation group (TG) which means they match each other on Chromosome 13. Here is what that TG looks like on a family chart:

judytgnicholson

The same segment of DNA from Chromosome 13 has come down to these 3 women. We know that the DNA was from either William Nicholson or Martha Ellis but we don’t know which. So when I said that this was her Nicholson DNA, it could really be either Nicholson or Ellis DNA – but not both.

In addition, like the next example below, Joan and Carol can know something else. They can know that the 51.4 segment that they share on Chromosome 13 is with Carol’s grandmother, Nellie Nicholson and not with Nellie’s husband. Before this match with Judy, they wouldn’t have known this.

a fine distinction on the Nicholson DNA

Here is an example of case #4 above where Judy matches both Carol and my mom, forming another triangulation group on a portion of Chromosome 18:

tg18

tgmomjudycarol

Again Mom, Judy and Carol all Share this specific segment of either William Nicholson or Martha Ellis. There is something else interesting about this chart. Judy and mom share that same DNA from Ann Nicholson. Usually when Mom and Judy match, they wouldn’t know from which of the couple the DNA came from. In this case their Chromosome 18 match came from Annie Nicholson.

That means Judy and my mom could assign that part of their DNA to Annie Nicholson. Also I could modify the Chromosome map for my mom that I did earlier in the blog. I think that I will do that.

chromomap18rev

On Chromosome 18, what I had as red is now in yellow. That means that the information is more specific. Interestingly, the orange on that Chromosome would also be from Annie, but because of who was matched to get to that, we say that it would be from one of Annie’s parents. It gets a little confusing. So at the point where the bar goes from yellow to orange, we are seeing further into the past when we see the orange part.

The practical part is that whenever someone matches my mom’s maternal side on that portion of Chromosome 18, she will know that it is a Nicholson (or Nicholson ancestor) match and not a Lentz match.

What about me?

I wonder if I share any of this Annie Nicholson DNA. Here is how Judy matches my brother Jon and 2 sisters Sharon and Heidi on Chromosome 18:

judychr18

Below is a chromosome map that I updated now that my brother’s  DNA results are in. This indicates the DNA that my 3 siblings and I got from our 4 grandparents. The maternal side is in orange and green and the paternal grandparents are shown in purple and blue. My brother Jon’s yellow match with Judy above is within the orange area of the bottom F bar below. Sharon’s green bar match with Judy above corresponds to the second orange segment below on the S row. Heidi’s blue bar match above corresponds to her second orange (Lentz) segment below on the H row. I match my mother’s father’s Rathfelder side for most of Chromosome 18. That is shown in green in the 4th bar below (J row). So I didn’t inherit any Annie Nicholson DNA here where my 3 siblings did.

chr18maprev

This method maps to our 4 grandparents, so Nicholson is not shown. Annie Nicholson is one of my 8 great grandparents. However, we now know that two of my sisters’ and my brother’s orange bars came from our great grandmother Annie Nicholson by way of her Lentz daughter.

Judy’s Lentz (or Nicholson) DNA

Speaking of Annie Nicholson, here she is with her husband Jacob Lentz:

Jacob Lentz

Below is another triangulation group from Chromosome 1 that Judy is in with my mom and Joshua:

judymomjoshuatg

Here is the family chart again:

tg1chart

This time the DNA may be from either Jacob Lentz or Annie Nicholson – but not both. This same segment of DNA came down 2 generations to my mom, 3 to Judy and 5 generations to Joshua. We might guess that this is Lentz DNA. That is because there are no Nicholson only matches there, but we don’t know for sure.

The Rule of the 1st and 2nd Cousin Combo

In two of the examples above, there was a 1st and 2nd cousin combo – including a triangulation group.

In the first case, Carol and Judy are 1st cousins, once removed. As such, they couldn’t tell which grandparent’s DNA that they shared (Nicholson or Nicholson spouse). Enter my mom as Carol’s 2nd cousin. She is further out relationally and they match on the Nicholson Line at Carol and mom’s great grandparent level. This identifies Carol and Joan’s DNA as coming from the Nicholson side. How is this helpful? Now anytime that Joan and Carol match someone on that same segment, they will know that the match has to be along the Nicholson Line going up through the Nicholson ancestors. This narrows down the possibilities a lot.

The rule: In a triangulation group between a 1st cousin and a second cousin, the second cousin will be able to identify which grandparent the 1st cousins share.

I’m sure that is why it is said that it is important to test second cousins. The reason that I haven’t come upon this situation before is that this combination hasn’t come up on my father’s side. I have results of my father’s first cousin’s DNA and my own 1st cousin’s once removed, but no second cousins to compare.

Summary and Conclusion

  • Cousin Judy has been helpful in filling in my mom’s Chromosome map
  • Judy’s DNA results will also be helpful also as I fill in my siblings’ and my own chromosome maps.
  • Judy’s results have partially phased the DNA. That means, for my mom she can tell at least for one area, not only where she has a maternal match, but also that it is a maternal grandmother match (Nicholson).
  • I had thought that there would be a way to identify some of the Lentz DNA. However, I don’t see a way without finding a Lentz cousin who doesn’t descend from the Nicholson side. This would have to be a second cousin or further out.
  • Once Nicholson DNA is identified, it is more likely that the remaining non-Nicholson DNA could be from the Lentz side. However, that is not sure, it just represents more than a 50% likelihood.

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