1

What does it mean when it is stated that you have 8 shared segments with a particular individual?

1 Answer 1

7

"8 shared segments" means there are 8 separate sequences of over a "significance" threshold (this is often 7 centimorgans or cM) within which you match the other individual. To be included in one of these matching segments, each base pair must be at least a half match.

Below is an illustration of the 2 shared sequences I have with my uncle on the first chromosome pair. The illustration (from gedmatch.com) shows base pairs with a half-match in yellow, those with a full match in green, and those with no match in red.

shared segments example

Broadly speaking, the more sequences of above a certain threshold, the more significant the match. This threshold depends on the context (for example, in endogamous populations where there has historically been a closed gene pool, a match might have to be longer (e.g. more centimorgans) in order to be considered significant. In my experience, a sequence of at least 20cM tends to indicate a match that has the potential to be traced.

0

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.