Understanding Genetic Matches on An Overview of Centimorgans and First Cousin Relationships

The range of centimorgans (cM) for your first cousin matches on , ranging from 690 to 1432 cM, is quite intriguing and can provide valuable insights into your genetic relationships. In this article, we will break down the key concepts of centimorgans, explore the genetic relationship between first cousins, and understand the variability in cM values.

Understanding Centimorgans

Centimorgans are a unit of measurement used in genetics to express the length of DNA segments. The more centimorgans you share with someone, the more closely related you are. This measurement is particularly useful when analyzing genetic relationships on platforms like

The Genetic Relationship Between First Cousins

First Cousins typically share between 575 and 1300 cM of DNA. This range is quite broad, and the higher end of this spectrum may include more distant relatives or be influenced by the genetic diversity within the family.

Understanding Variability in Centimorgan Values

The range you see—from 690 to 1432 cM—suggests a few possibilities:

Closer Relationships

Some of your matches may be more closely related than first cousins, potentially indicating additional shared ancestry. For example, they could be half-first cousins or even more distant relatives.

Overlapping Family Trees

In some cases, individuals may have multiple shared ancestors, leading to higher cM values. This could be due to shared lineage from multiple branches of the family tree.

Genetic Recombination

Genetic recombination is a natural process that can cause variability in how much DNA is shared among close relatives. This explains why the values can vary even among closely related individuals.

Interpreting Higher Values

If you see values exceeding the typical range for first cousins, it could indicate:

Half-First Cousins or More Distant Relatives

You might be looking at half-first cousins who share about 400–800 cM or other relatives like a first cousin once removed.

Endogamy in Your Family Tree

There could also be some endogamy (inbreeding) in your family tree, where relatives marry within a specific community, leading to increased shared DNA.

Conclusion

While the range of cM suggests that most of your matches are indeed first cousins, the higher values might indicate additional familial connections or more complex ancestral relationships. To further clarify these relationships, it may be useful to explore your family tree or reach out to your matches for more information.

Your shared DNA is within the typical zone for first cousins. The differences in cM values are based on the way chromosomes split and recombine between your shared grandparents and the chromosomes of your respective parents, and then between your respective parents and their children (you and your cousins). You may have a lot of a particular great-grandparent's DNA, such as your grandmother's father. Your cousin that matches you most likely has a significant portion of it too. The cousin that matches you the least might have less, but they may have more of your grandmother's mother's DNA.

Your relationship does not change because of this variability. It is a normal occurrence in family genetics.