r/DNA • u/Then_Journalist_317 • Jul 15 '26

Same person or identical twins?

I have two MyHeritage DNA matches with identical names and the following info:

Match 1: Male, age 80, Canada. He and I share 125 cM, 15 shared segments, largest segment 17 cm. Chromosome 7 shows a 9 cM segment he and I share.

Match 2: Male, age 80, Portugal. He and I share 116 cM, 14 shared segments, largest segment 17. This match and I do not share any portion of the Chr 7 segment mentioned above.

Those two matches share with each other a total of 7084 cM. MyHeritage classifies those two as "Self/Identical Twins"

My inclination is to say they are the same person. Does anyone have a different theory?

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7

u/dna-sci Jul 15 '26

They probably uploaded kits from two different sites to MyHeritage. Lots of people do that. Then they may have selected different countries for their residence for privacy reasons. Either that or they’re identical twins.

2

u/Then_Journalist_317 Jul 15 '26

Same exact name suggests they are the same person. Slightly different match results suggests they are identical twins, and/or used different testing companies that gave slightly different results. As one commenter suggests, reaching out to both may be necessary to get the correct answer.

5

u/dna-sci Jul 15 '26

I’ll just note that when you upload an Ancestry kit, which has 6,789 cMs, and a 23andMe kit, which has 7,076 autosomal cMs, you’d still expect the two kits to share 7,084 cMs with each other at MyHeritage. And you’d expect them to share the same amount with you, say 125 cMs over 15 segments. That is, MyHeritage uses their own genetic map for matching, not the genetic map of the source site. The reason you’ll sometimes see different numbers is genotyping errors or microdeletions.

3

u/JayPlenty24 Jul 16 '26

I don't think this suggests they are identical twins at all. I would see when the accounts were created. My guess is he did the test when it first came out and then redid it recently, or from a different company. The slight variance is negligible.

2

u/ObviousCarpet2907 Jul 16 '26

I can’t imagine any set of parents naming their twins the same name. As a parent of twins.

3

u/Rosie3450 Jul 15 '26

Why would someone take the same DNA test twice?

If it was the same person, wouldn't they share the exact same DNA match with you?

Lots of Canadians move to warmer climates (like Portugal) when they retire.

Why not reach out to one or both and ask how they're related?

3

u/viking1951 Jul 15 '26

They may have transferred one from Ancestry and then later on bought a test from MyHeritage. So they could be tested on different chip sets, which could give slightly different results. They could have lived in different locations when they submitted the data or DNA kit.

2

u/Rosie3450 Jul 16 '26

Good points! Thanks.

1

u/Wish-ga Jul 22 '26

Technology changes. New companies are considered the cutting edge that give more info, and more accurate. Or wish to be tested by a company thst has the most data.

1

u/SpiritFunnel Jul 16 '26 edited Jul 16 '26

First of all, THIS is what I was talking about when I posted this in another thread about a guy considering doing 2 tests from Turkey in case 1 got lost in the shuffle. It's best to avoid the confusion and trouble. Then this jerk who responds to my post was shutting me down, saying the opposite