What is Endogamy?

Endogamy is the practice of marrying within one specific group. It is usually an ethnic group, but it can also be a social group or caste.

It’s a common practice and is not the same as incest. However, it does increase the risk of genetic disorders within a group. Endogamy is legal, practiced by many religious and ethnic groups.

Endogamy is the practice of marriage within a specific group. While usually done within ethnic groups, it can also be a social group, tribe, class, or caste.

It’s a common practice as part of tradition and beliefs. However, it is not the same as incest. Endogamy is legal and is practiced by many ethnic and religious groups and cultures.

The practice of marrying exclusively is not considered wrong. However, it does carry an increased risk of genetic disorders within a group.

Why Do People Practice Endogamy?

Endogamy is the practice of marrying within a particular group, tribe, or caste. It can be intentional, or it can occur by accident.

Some communities want people to marry within the same religious groups. Others intermarry within the same ethnic groups based on cultural practices. Or it can be a combination of both of these things.

In other cases, there isn’t much choice. Usually, they are people who live in isolated communities. They don’t have access to travel and don’t have much chance of meeting anyone. This was the case in the past more than it is now, but these isolated communities still exist.

Sometimes, incidents of endogamy occur just because.

Let’s say your mother and her sister grew up in a house across the street from your father and his brother. Everyone spent a lot of time together and got along. There might have been no restrictions or cultural traditions. By chance, your family created an endogamous relationship when you and your cousin were born.

With endogamy, cousin marriages are fairly common.

How Does Endogamy Affect Genetic Matching and Ancestral Research?

One of the effects of endogamy is the risk of genetic diseases. But aside from that, there is another aspect to consider. Marrying within groups can make genealogical research easier or more complicated. It depends on the specific circumstances.

People without endogamous relationships have to find eight sets of great-grandparents. However, people who have endogamy in their families must locate fewer. The same couple will appear on multiple lines in their genealogy results.

Additionally, it’s easier to trace people and family history when relationships were more insular.

Let’s say your family was Acadian Catholic, and you want to know more about your heritage. It’s easier to research. If you know you descend from a group of people who are inclined to practice endogamy and they attended a church in a certain area, chances are church records will be enough to help you identify your entire family.

The church kept detailed records of all marriages and required non-Catholics to be baptized before marrying. You’ll have access to a lot of information that is already organized. Plus, they are easily located from one resource.

It would be a different story, though, if your ancestors practiced a religion that did not keep such detailed records or had its records destroyed. In these cases, endogamy makes your research more complicated.

Communities that most often practiced endogamy include: 

• Ashkenazi Jews
• Native Americans
• Acadians
• Amish
• Mennonites

Without detailed record-keeping, it isn’t easy to make distinctions with so much overlapping DNA.

For example, let’s say your aunt on your mother’s side married your uncle on your father’s side. This creates a double cousin scenario in your family tree.

Not only do you share DNA with your cousin because her mother is your mother’s sister, but you also share DNA on your father’s side because her father is your father’s brother. You are maternal and paternal first cousins, which means you share twice the amount of DNA shared by first cousins.

Endogamy and Genealogical Relationships: The Tricky Part

In a standard DNA test, the company to which you submit your sample does not know that your family practiced endogamy. This is because endogamous populations cannot be easily distinguished.

A double first cousin would look like a half-sibling on paper. She has approximately the same amount of DNA that you’d share with the same mother or father. It’s even more complicated when this relationship was further back in your family tree and happened with your grandparents or great-grandparents.

And because endogamy rarely only occurs once in a family, most people end up sharing a lot more DNA with their cousins than you’d expect.

With marriage within a specific group, it’s challenging to determine genealogical relationships. DNA overlaps in your community, not because of one recent common ancestor, but because you share multiple distant relatives in common.

What Does an Endogamous Relationship Look Like When Conducting Genealogical Research?

It depends.

You’re not going to get any obvious signs or triggers telling you that endogamy occurred on DNA test results.

One of the best ways to spot an endogamous relationship versus an exogamous relationship is to notice the total amount of DNA you share and the DNA's size. Most DNA testing companies provide this information. You’ll be examining the total DNA shared, the number of segments shared, and the length of the largest segment.

If this seems complicated, your best bet is to take your DNA test results to an expert analyst who can help you make sense of what you are looking at. They’ll assess your genetics, and then you can take that information and apply it to your genealogy. They also offer services where they can help you analyze the genetics on your own.

It’s also important to consider geographic location. Where you live and the areas where you know your ancestors lived rule out some groups. A thorough genetic study, paired with efficient statistical analysis of available data, is needed. This is especially true for extended families with very limited information.

Endogamy and Genetic Disorders

A consanguineous marriage happens between two people who have at least one common ancestor. Clinically, it is defined as the marriage of two people, related to each other as cousins. 

The following conditions are commonly seen inside endogamous communities: 

• Stillbirths and increased risk of abortions
• perinatal mortality
• congenital malformations
• autosomal recessive disorders
• many more complex diseases

Community disease profiles among endogamous groups vary from one group to another. The diagnosis and detection of complex diseases in humans as effects of endogamy is an ever-growing process.

With continuous technological advancement, however, success is on the horizon.