Grandmother? Or Great Aunt?

[Seekingthetruth]

Forgive me if this is not the appropriate forum for my question. I welcome any and all suggestions here.

Backstory.. My now deceased mother suspected that her aunt may have been her mother but it's always been denied. Fast forward to DNA testing and my mother's "aunt" and her daughter and grandson are showing a significant amount of DNA in common with me. What do I need to look for/compare in the numbers to determine if they are my Great Aunt, 1st cousin 1x removed, and second cousin OR Grandmother, half aunt and half first cousin?

I will call the aunt G, her child T, and her child J.
G shares 1124 centimorgans with me, with the longest block 100.
T shares 759 cm's with me, 79 being the longest block.
J shares 410 cm's with me, 36 being the longest block.

From what I can gather, they could be either set of relationships. What am I missing??

Thank you for reading,
Seekingthetruth

[ltd-jean-pull]

For this question the only shared DNA that matters is that shared by you and G, and you're right - the amount you share is lower than average for a grandparent-grandchild and higher than average for a gt-aunt-gt-niece/nephew.

Ignore the shared amounts with T and J because they don't add anything. It's your relationship to G that matters.

Do you have any siblings who would test?

[loobster]

Just to be clear, in case it might make a difference, are we talking any of the endogamous groups (such as Jewish or American Colonial)?

[Seekingthetruth]

Not Jewish and am not sure about endogamous groups being a factor. How do I determine this? I have a half sibling who would test so maybe that's the best course of action.

[mollyblum]

Not Jewish and am not sure about endogamous groups being a factor. How do I determine this? I have a half sibling who would test so maybe that's the best course of action.

Just for comparison- I share 1742 cM w/ 92cM with my Uncle so your number really isn't that off. If you feel really strongly test your 1/2 sibling.

[jova99]

grandmom

so you suspect your Great Aunt may be your Grandmother ?

My daughter shares 1707 cm with my mother (her grandmother), largest segment is 219

my daughter shares 1699 cm with her maternal grandmother, largest segment is 122

my daughter shares 1116 cm with her Great Aunt, sister of my mother. Largest segment 168