Sharing 360CM with 1st cousin

[Varg Vikernes 2]

Not sure if this is off topic, but I thought I met get some decent advice here as I have tried elsewhere and not been able to get anywhere.

Me and my maternal 1st cousin (her dad and my mum are siblings) have both done 23andMe tests and have a shared centimorgan count of 360. From what I've read this is very low for what is expected of a known 1st cousin relationship and more likely a half cousin relationship. However, I don't want to simply take this on face value without doing further research because the implications are problematic.

DNA aside, there really is no reason to believe my uncle is not my grandfather's son. I have looked at our Shared Matches list but I can't tell if they are just matching through 1 grandparent or 2 because none of them are close enough for me to be able to figure out the relation.

Are there any previous example or precedent of 1st cousins having this low a centimorgan match, or anyone who has any anecdotes that relate to this situation?

P.S: Through uploading to MyHeritage I have confirmed relationships through all 4 of my grandparents so know that there can't be any infidelity on my side. My cousin is no longer alive so I can't ask her to do the same.

[Graham]

Had a look at my mum's cousin who she matches. 14.2% (1,006.0‎ cM).

That is quite low.

[Nurzat]

those things are more common than we think. I've only recently found out my greatgrandma was a soldier's daughter (he only was around during war and then left to his region), this bringing me 1/16 ancestry from that region and that some other very close relative is not his father's son. so..

[Varg Vikernes 2]

those things are more common than we think. I've only recently found out my greatgrandma was a soldier's daughter (he only was around during war and then left to his region), this bringing me 1/16 ancestry from that region and that some other very close relative is not his father's son. so..

I'm not disputing that this is sometimes the case, but apart from the centimorgan count we don't have any reason to suspect illegitimacy.

[Varg Vikernes 2]

those things are more common than we think. I've only recently found out my greatgrandma was a soldier's daughter (he only was around during war and then left to his region), this bringing me 1/16 ancestry from that region and that some other very close relative is not his father's son. so..

Also sounds like the first case you talked about was a known case of illegitimacy as opposed to a hidden one.

[gixajo]

Not 23andME but My Heritage, this is how much my father shares with a first cousin of him:




ADN compartido(Dna shared) 11,2% (790,8‎ cM)

Segmentos compartidos(shared segments) 30

Segmento más grande (longest segment) 69,2‎ cM