Is a DNA match with a very high X-DNA cM value always valid (or could it be a false-positive)?

What does X match mean in DNA results?

When an XY male finds someone who is a match for their X-DNA, it means they have a shared ancestor with that person on their mother’s side. However, it’s rare for an X-DNA test to be done on its own. That’s because this test only looks at one chromosome and therefore yields more limited results about your ancestry.

What does X match mean on Gedmatch?

What is an X DNA match on Gedmatch? An X DNA match is a person with whom you share at least one segment of DNA on your X chromosome.

How many Centimorgans is a good match?

Centimorgans (cM) are units of genetic linkage between two given individuals. For example, if you share 1800 cM with an individual, that means you share around 25% of your DNA with them. A strong match will have around 200 cM or more.

What does it mean if you share DNA on the X chromosome?

Maternal uncles and nephews would be expected to share segments on their X chromosomes whether their parents were related or not. On the other hand, if we are talking about a paternal uncle’s X chromosome, then sharing big chunks of the X chromosome could mean that the parents may have been at least distantly related.

Can you share DNA and not be related?

Yes, it is possible to share a small amount of DNA with someone and not be related. In other words, it’s possible to share genetic material and not share a common ancestor or any identifiable genealogical connection.

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