How Much DNA Do Cousins Share?
A blog post by Cyber Search.
Understanding the Genetic Connection
Cousins are often among our closest relatives outside of our immediate family, and the amount of DNA they share can tell us a lot about the intricacies of our family tree. When it comes to the question of how much DNA cousins share, genetics provides us with fascinating insights. First cousins, for example, share about 12.5% of their DNA, due to the fact that they have a set of grandparents in common. This percentage means that, on average, there is a one in eight chance that any given gene in your DNA will match that of your first cousin.
Variations Among Different Types of Cousins
The shared DNA percentage changes with further removed cousins. Second cousins, who have the same great-grandparents but not the same grandparents, tend to share about 3.125% of their DNA. Third cousins, sharing great-great-grandparents, can expect to share about 0.781% of their DNA. It's important to recognize that these figures are averages and the actual shared DNA for any two cousins can be slightly more or less.
Practical Implications of Shared DNA
Knowledge about DNA sharing can be used in a variety of circumstances, ranging from satisfying curiosities about your ancestry to more practical applications such as health screenings. Understanding the shared DNA among family members is crucial for genetic testing, where it can help identify the inheritance patterns of certain genetic conditions. It is also an essential piece of information for those looking into their family history and trying to figure out how closely they are related to newly discovered cousins.