MARCOTTE, MARCOTTE, MARCOTTE

(An Endogamy Nightmare)

If you're not a genealogist, you may never have heard the word "endogamy."  Google defines endogamy as, the practice of marrying within a specific social group, religious denomination, caste, or ethnic group.  It can be the result of cultural pressure, a conscious decision, or geographical isolation.

So, why is endogamy such a nightmare?  Well, it can make it difficult or even impossible to find birth parents and family members using DNA.  A case I was recently working on is a great example of this.  In fact, it was the most difficult endogamy related case I've ever seen.  The DNA data and family trees were so unclear and confusing, I just couldn't solve it.  It involved a family named Marcotte.  Before getting into that, I'll give you a simple example of endogamy so you can see what I mean. 

Let's say your grandparent's names were Marcotte and Jones, and they lived in a small rural town where everybody knew everyone's family.  Maybe there were only a few families living in the area.  Let's go back to the 1800s or early 1900s.  Back then, traveling long distances wasn't easy.  New people coming into town may have been a rare occurrence.  So, there weren't a whole lot of people to choose from when looking for a spouse.  After a few generations, you'd likely end up with a town full of people who all had some genetic relationship to each other.  This is a perfect example of endogamy.  Take a look at this tree...

Notice your grandmother's mother was also from the Marcotte family, as shown in the tree above.  Your grandparents could be related to each other.  Maybe they are first, second, third, or more distant cousins, but that relationship will likely alter the DNA levels and cause confusion when figuring out relationships.  If you think this is rare, think again.  Marrying a cousin, even a first cousin, wasn't that rare long ago.  This kind of thing usually results in a fairly simple DNA problem that can be solved though.

In the tree above, we only see an issue with Marcotte.  All the other lines have different names.  Let's say we discovered your grandparents are second cousins.  So, if you noticed your DNA matches related to Marcottes had slightly higher than normal centimorgan values, that would make perfect sense.  It might cause a little confusion with the numbers, but it's not too big of a problem.  Having your grandparents being second cousins won't alter the DNA levels too much.  Now let's see what happened in the case I was dealing with.  Here's another tree...

The tree shown above uses real names involved in the case I was working on.  Everyone was from a rural area of Louisiana.  Take a close look at what's going on here.  The mother and father in this tree are both related to Marcottes.  It's way more complex that that though, notice there are two Marcotte grandparents, three Marcotte great-grandparents and five Marcotte great-great-grandparents.  Hold one, the fun doesn't end there.  There are multiple Ducotes, multiple Gauthiers, and multiple Bordelons as well.  I traced all these lines back several generations and guess what, they're all related to each other.  Everyone in this tree is related to everyone else in this tree in some distant way, and sometimes, not so distant.  There's even a Marcotte marrying another Marcotte.  There's even a town in Louisiana called Bordelonville where all those Bordelons came from.  Everyone is related.

So, what's the DNA look like in this case.  Well, there's no other way to put it other than to say, it's a complete mess.  I was seeing large numbers that would make it appear to be easy, but the numbers were so large because DNA was coming from so many different lines of the tree.  I couldn't solve it with DNA and family tree data.  If you were going to try to come up with centimorgan values that would work, you'd have problems doing so because those numbers can vary so much.  For example, let's say you thought someone was your second cousin on one line, but also your third cousin on another line.  You can't really figure that out with a number.  A third cousin may give you a value of something like 50cM to 150cM.  A second cousin could give you 150cM to even 400cM.  This DNA match could range in value from 200cM to 500cM.  You end up getting too wide of a range to rely on numbers.

How can we solve these kinds of problems?  The only hope in this case was to use the little information we had and hope to find someone who might know something.  In this case, the woman I was helping was adopted and only knew her birth name was Marcotte.  I've narrowed it down to a few people I think it can be, but can't prove anything with DNA data.  We need to find someone who was aware of an adoption at the right time and in the right place involving these families.

Look for more posts coming soon.