My Father In Law’s Autosomal DNA: Separating the LeFevres from the Pouliots

It’s been a while since I’ve looked at my Butler father in law’s autosomal DNA, so it’s time to look at it in a blog. Richard descends from an Irish father and a French Canadian mother. Richard has many large matches with many with French Canadian ancestry. In comparison, he seems to have smaller and fewer matches on his Irish side. This is probably due to several reasons:

  • The French Canadians have been around for many hundreds of years in North America.
  • Their descendants have spread throughout the region and many migrated to Massachusetts where Richard is from.
  • Many of these early French Canadians were intermarried. This tends to increase the amount of shared DNA among cousins.
  • The numerous French Canadian descendants perhaps were more likely to take DNA tests.
  • Conversely, the Irish relatives tended to emigrate later in time.
  • These Irish descendants seem less likely to have taken DNA tests.

Richard’s Known Matches – French Canadian

Richard has 2 pairs of known matches with cousins of French Canadian ancestry (other than my wife). They are:

  • 2 First cousins – They are on his mother’s (LeFevre) side
  • 2 Second cousins – They are also on the mother’s side but one generation up. The common ancestor is Pouliot. Here is a diagram of Richard’s mother’s side:

Pouliot LeFevre Diagram

My Confusion

I looked at these matches and wondered how I would be able to sort out the LeFevres and the Pouliots. This was confusing as the LeFevre line had Pouliot in it.

The Easy Answer

The easy answer is there is no easy way to pull the 2 apart with what I had. This is because at the first cousin level, it is not easy to pull out one family. If you think about it, your first cousins share 2 grandparents with you. This was the case with Richard’s 2 first cousins also. As they are on the mother’s side, they are useful for determining whether matches are on the Butler or LeFevre (Paternal or Maternal) side, but not a whole lot more. But that is quite a bit. This is a way of phasing your results. This also separates the French Canadian matches from the Irish matches.

Looking for more than can be found in a relationship can be frustrating and confusing and that was where I was a while back. I have found that it is usually good to keep it simple – especially when figuring these things out. The problem was I was comparing apples and oranges. Or in this case 1st cousins and 2nd cousins. This is why it is sometimes suggested that a second cousin is a good choice for testing.

The Pouliot Second Cousins

As mentioned above, the Pouliot second cousins represent all the Pouliot DNA shared. On the FTDNA Chromosome Browser Richard’s DNA shared with his 2 Pouliot 2nd cousins looks like this:

Butler Pouliot Chromosome Browser

From the image above, I gather a few things:

  • This is a map of the DNA that Richard received from his Pouliot great grandfather (and Fortin great grandmother) down from his Pouliot grandmother.
  • As this represents the DNA from Richard’s grandmother, it would theoretically cover about one half of his chromosome browser. This would be the amount of DNA that he actually did get from his grandmother as compared to how he matches his two 2nd cousins.
  • Richard’s theoretical amount of DNA he got from his grandmother would cover half of the browser because the browser contains both paternal and maternal matches.

Add in the 1st Cousin

I’m only adding in one LeFevre 1st cousin as the other one didn’t test at FTDNA. Here the first cousin will be in green.

French Canadian to Richard in Browswer

From looking at the above, I observe the following:

  • The green area represents Richard’s maternal side as shown through a match with a maternal cousin.
  • This green represents LeFevre on Richard’s parent level.
  • About one half of his green match represents LeFevre and one half represents Pouliot on the grandparent level.
  • Going further up the ancestor line the green represents every other ancestor of Richard’s mother. This would be French Canadians.
  • Richard got a full chromosome from his mother, so all the DNA received from his mother would fill the above chromosome browser.
  • There are areas on Chromosomes 1, 13 and 16 where Richard’s green LeFevre cousins matches overlaps with his matches from his Pouliot cousins. These areas likely represent where the LeFevre cousins match the Pouliots. This would mean that in this area of the LeFevre cousins’ chromosomes they got their DNA from the Pouliot side. I know that I said above that it was not possible to sort out what part of the LeFevre DNA was from Pouliot, but from looking at the Chromosome Browser above, it appears that it is possible. More on this later.
  • Areas where there are breaks in the matches or where the matches go from the LeFevre cousin to the Pouliot cousins likely indicate Richard’s crossover points. These are the points where the DNA he received changed from one [maternal in this case] grandparent to another. That is, the DNA he actually received went from his LeFevre grandfather to his Pouliot grandmother.
  • As the LeFevre cousins and Richard both descend from LeFevre sisters, they share X Chromosome matches. Both those sisters got their X Chromosomes from their 2 parents. Those 2 parents were LeFevre and Pouliot.
  • Due to the X inheritance patterns there can be no X Chromosome matches between Richard and his Pouliot 2nd cousins. Richard did receive Pouliot X Chromosomes from his mother’s mother. But Richard’s cousin did not as there is no X Chromosome passed down from father to son.

Triangulation – Thinking In Three Dimensions

Triangulation is when 3 or more people all get their DNA from the same ancestor and all match each other. Our best shot at finding this is at the right hand side of Chromosome 1. It looks like these 3 people who match Richard should match each other. Two are siblings, so that is a given. Here is how Richard’s 4 cousin matches look like at Gedmatch.com:

Richard Gedmatch Chr 1

You will have to switch gears a bit here from the FTDNA browser. In this browser, the different colors stand for the size of the match. Here, #1 and #2 are the Pouliot 2nd cousins. #3 and #4 are the LeFevere 1st cousins. #4 was the cousin that didn’t test at FTDNA. As expected, in the area where the 4 cousin matches are stacked on top of each other, they also match each other. At this close of a match, they almost have to. The only other option would be if they matched somehow on Richard’s paternal Irish side, which would be unlikely. This means that the 5 cousins triangulate and they have as a common ancestor their great grandfather Pouliot. Another interesting thing about Richard’s Chromosome 1 is that with just 4 maternal cousins, he has much of his chromosome mapped out – at least the maternal side of it.

 

 

 

 

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