Author Topic: Is it possible to share 215 cm and not be second cousins?  (Read 595 times)

Offline GingerVicky

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Is it possible to share 215 cm and not be second cousins?
« on: Thursday 24 December 20 11:32 GMT (UK) »
Hi there,
I have a DNA match who I share 215 cm with and the website says we are probably 2nd cousins. Is it possible to share that much cm but be related further back? I know all my 2nd cousins so am very confused by it. My family is not huge.
I have known them to say I only share a tiny amount of cm with a closer match, just wondering if it worked the other way round.
Thank you
Vicky

Offline Flemming

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Re: Is it possible to share 215 cm and not be second cousins?
« Reply #1 on: Thursday 24 December 20 12:27 GMT (UK) »
Have you checked DNA Painter's shared cM tool?

https://dnapainter.com/tools/sharedcmv4-beta

There also could be a double relationship further up the tree - for example, two sisters marrying two brothers (you descend from one couple, the match descends from the other). That would amplify the shared cMs lower down.

Offline GingerVicky

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Re: Is it possible to share 215 cm and not be second cousins?
« Reply #2 on: Thursday 24 December 20 12:35 GMT (UK) »
Thank you. I hadn't thought of that.


Offline GingerVicky

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Re: Is it possible to share 215 cm and not be second cousins?
« Reply #3 on: Sunday 27 December 20 15:46 GMT (UK) »
Interestingly after you posted this I started looking into my father's side of the family where I know there are quite a few inter connections and found a cousin (ancestry says we are 2nd cousins twice removed) who was born in 1890 and I am related to all of his grandparents (I'm a direct descendant on each line). I haven't been able to find any descendents of his but if he had some surely we'd share quite a lot of centemorgans through being related in 4 different ways.
Fascinating and also hard to make sense of it.

Offline JohnDoe2020

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Re: Is it possible to share 215 cm and not be second cousins?
« Reply #4 on: Friday 12 February 21 22:52 GMT (UK) »
Yes you are right. Pedigree collapse occurs when there are multiple connections through generations, cousins marrying cousins as an example. It does modify the apparent CM percentage which may skew your apparent relationship, although it is not typically a large shift.

Offline Gadget

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Re: Is it possible to share 215 cm and not be second cousins?
« Reply #5 on: Saturday 13 February 21 00:40 GMT (UK) »
I have a few of these multiple relationships on one of my lines. The cMs suggest a closer cousinship than actually exists. The shared ancestors all lived in a small mining village. Once I'd examined the trees - or reconstructed them - it became obvious that we descended from 2 or more lines.

Gadget
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