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What is Endogamy?

Have you heard of endogamy or seen signs of it in your family tree? In this post, learn the definition of endogamy and why most people have it in their family tree.

In addition, you will also discover:

  • Examples of endogamy
  • The difference between endogamy and pedigree collapse
  • How endogamy affects DNA

Endogamy is a word that is frequently tossed around in genealogy circles. But what does it actually mean?

What is Endogamy

Most importantly, how do you know if you have endogamy in your own family tree?

As you will see by the end of this post, endogamy is not strange or uncommon. In fact, we all have it to some extent.

What is the definition of endogamy?

Endogamy is the custom or practice of marrying within the same social or ethnic group, local community, or religious tradition. In addition, endogamous groups tend to require this practice, either by law or tradition, and discourage marriage between members of their group and outsiders.

Even though endogamy is usually occurs where it is encouraged, it isn’t always seen only because it is required. For example, sometimes there are limited partners to choose from, and so endogamy occurs because there simply are no outsiders.

For example, think of a place that is geographically isolated with a small founding population. Even if the original founding population is not closely related, after several generations, most people will be distantly related to each other.

In many parts of the world, endogamy is no longer fashionable, especially in societies where people have seemingly unlimited access to unrelated (or very distantly related) partners. This is why many people tend to be surprised when they find evidence of endogamy in their family tree.

Historically, however, it just wasn’t a big deal.

What is an example of endogamy?

There are endless examples of endogamy around the world. Well-known examples of endogamy include the Ashkenazi Jewish communities of Eastern Europe and the diaspora, descendants of early European immigrants to the British Colonies in North America, French Canadians, and those with indigenous North and South American ancestry, including many people with Mexican ancestry.

Even though those large groups of people that I mentioned above are some of the most well-known examples of endogamy, we don’t have to look very hard to find other endogamous groups. For example, my own Slovak ancestors were from the same isolated region of Slovakia, and I have found ancestors repeated multiple times in my Slovak family tree.

What is the difference between pedigree collapse and endogamy?

While endogamy is the practice of marrying within the same group over the course of many generations, pedigree collapse is when it happens just once, or a few times, on different lines of your family tree. Pedigree collapse can be easily spotted on our family trees, too.

Sometimes, endogamy is confused with the idea of pedigree collapse. However, they are not the same thing.

Just yesterday, I was reading through a document that one of my great-grandfathers wrote about his life history. He mentioned that he briefly dated one of his second cousins while he was a student in high school.

Eventually, he went off to college, met my great-grandmother, and the rest is history. For a while, however, it did look like his life might have taken a different course.

It makes perfect sense that my ancestor was dating a cousin. They spent time in the same social circles and were probably encouraged to spend time with each other.

In fact, based on what I could ascertain from the story of my grandfather’s second cousin’s life, her parents died while she was still a child. After the death of her parents, she went to live with an aunt and uncle in Chicago.

It seems perfectly plausible that she may have been encouraged to consider marrying her cousin, as they came from families with a similar background. In addition, my great-grandfather’s family could have encouraged the match because even though she no longer had the financial stability that her parents could have offered her, the fact that she was a cousin may have rendered that fact irrelevant.

If my great-grandfather had married his second cousin, this would be an example of pedigree collapse. However, if this occurred generation after generation, whether because it was encouraged by tradition or simply because there was no one else to marry, this would be an example of endogamy.

Are most marriages Endogamous?

In a technical sense, many marriages are endogamous. This is because most people marry people who are from the same social group as they are, and they tend to share language, religion, and cultural similarities.

This happens even when people do not try to marry within their group on purpose. Endogamy often occurs because there is little or no access to people from outside groups due to factors beyond control, such as geographic isolation.

Furthermore, people from the same cultural group likely share common ancestors, even if they are probably only very distantly connected and unaware of who their shared ancestors might be.

When we use the term endogamy, however, we are usually referring to marriages between closer family relationships, such as second, third, and fourth cousins. These cousins may not know exactly how they are related, but they likely do know that they have some sort of family connection – even if it is distant.

How does Endogamy affect DNA?

Endogamy can affect our DNA and relationship with our genetic matches because of the way that DNA is inherited. While we do not inherit DNA from all of our ancestors, we do inherit it from some of them, and even after several generations, we are likely to have at least one small segment that was passed down from any given ancestor from that generation.

If we share several ancestors within the past 6-8 generations with a DNA match, we might have multiple DNA segments in common with the match, since we both might have inherited the same segment passed down from all, or most, shared ancestors.

Endogamy can often skew the total amount of DNA that we share with a distantly-related DNA relative because of the multiple shared segments. A higher amount of shared DNA can lead us to mistakenly believe that our most recent common ancestor is more recent, and the genealogical relationship closer, than it really is.


I hope that this post has helped you understand a bit more about exactly what endogamy is, how it affects our family tree and DNA matches, as well as which factors influence it most.

If you have any questions about something that you read in this post, or if you would like to share your own example of endogamy in your family tree, I would love to hear from you in the discussion below.

Thanks for reading today!

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Darla Mueller

Sunday 25th of June 2023

I have a little different situation in my mother’s family. Her mother was one of 16 children living in a rural area of Oklahoma, and her father was one of 15 living at a neighboring farm. Her mother’s brother married her father’s sister, and there were supposedly one or two other instances of these neighboring families marrying. So these people were not related to each other, but it still led to an interesting, somewhat confusing genealogy. My mother refers to her cousins from this “intermarriage”, of which there were MANY, as double first cousins. Is this the correct term? And is there a term for this type of intermarriage? On another note, my father had a cousin who married her second cousin. When I discovered this while working on my family tree, I mentioned it to a cousin whom I had discovered through a DNA match and had been corresponding with through Ancestry. She was one of the children of this union, and when I inquired whether she was aware that her parents were 2nd cousins, I never heard from her again! In retrospect, probably not the wisest comment on my part. 😳😂


Monday 30th of May 2022

My own family tree I believe has examples of this. I descend from John Dowling I; He had 2 sons among other children.. oddly enuf my paternal grandmother comes from one & my paternal grandfather another; and apparently my family is famous as an inbreeding example ( Libby & Larrabee) intermarry many times on my tree.. it’s actually the focus of a published article for genealogy research…


Sunday 5th of June 2022

Hi Bernice, That's a great story! I am glad that you were able to research those lines of your tree to figure out that endogamy. If we look hard enough, almost all of us will be able to find some in our tree. Thank you for your comment :) Mercedes

Marena Arbelia

Sunday 14th of November 2021

There has been some talk that my paternal grandfather wasn't my grandfather, but that his brother, my great-uncle was actually my dad's dad. How would this show up in my dna and matches?

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