Identity by descent

Okay kiddo, have you ever heard of something called DNA? It's like a code that tells your body how to work and what traits you'll have, like your eye color and your height.

When you have DNA that is exactly the same as someone else's, it means that you have inherited that piece of DNA from a common ancestor. This is called "identity by descent."

For example, let's say your mom and dad both have a certain gene for eye color, and you also have that same gene. This means that you inherited that gene from both of them, and it's said to be "identical by descent" because it came from your common ancestors.

This concept is really important in research about genetics, because it helps us understand how traits and diseases are passed down through families. By looking at the similarities and differences between people's DNA, scientists can learn a lot about how our bodies work and how to keep them healthy.