Because there is randomness when DNA is transmitted from parent to child, the more distant a cousin pair the less likely they are to share any stretch of DNA that was passed down through the generations. Note that even though there is a relatively low chance of detecting more distant cousins, DNA Relatives will likely find quite a few given the large number of distant cousins that exist.
We estimate the probability of us detecting whether you share DNA with a cousin to be:
Cousin relationship | Probability that shared DNA is present and detected |
1st Cousin or closer | ~100% |
2nd Cousin | >99% |
3rd Cousin | ~90% |
4th Cousin | ~45% |
5th Cousin | ~15% |
6th Cousin and beyond | <5% |