Might someone help me sense check the logic behind my DNA detective work?

[snuttall]

My mum was illegitimate, the result of a one-night stand, as a result my grandfather has never been known.

I have a 104cM 2nd/3rd cousin match, and after pooling my shared matches, he appears be in an unknown 'pool' which may correspond to my missing grandfather. The match is the same age as me, so as I understand it, the likelihood is that we share great-grandparents or great-great-grandparents.

Conveniently, I'm English and this match is Australian and only has one English grandparent, which narrows things down. Additionally, my Mum was born in Lancashire, and the match's English grandparent hails from Lancashire!

So my next step was to look at the match's great-grandparents and great-great grandparents in that line, and their other children, and follow a process of elimination to find somebody who was the right age, and in the right location, to get my grandma pregnant in Blackburn, Lancashire, in 1928.

I was able to eliminate quite a few people who:

• Died or emigrated before 1928
• Was an unrealistic age e.g. very old or very young in 1928

This has left me with only five possibilities:

Match's 1C3R b. 1896 – married 1923 and lived in Leicestershire. 32 in 1928.
THIS WOULD MAKE ME THE MATCH’S 3C1R – 4% CHANCE

Match’s GG-Grand-Uncle b. 1881 – married 1906 and lived in Shropshire. 47 in 1928.
THIS WOULD MAKE ME THE MATCH’S 2C2R – 22% CHANCE

Match’s 1C2R b. 1891 – single and living in Manchester in 1911, later moved to Yorkshire. 37 in 1928.
THIS WOULD MAKE ME THE MATCH’S 3C – 22% CHANCE

Match’s 1C2R b. 1893 – married 1919 in Manchester, stayed in Manchester. 35 in 1928.
THIS WOULD MAKE ME THE MATCH’S 3C – 22% CHANCE

Match’s 1C2R b. 1897 – did not marry, died London 1942. 31 in 1928.
THIS WOULD MAKE ME THE MATCH’S 3C – 22% CHANCE

My grandma was 35 in 1928 when the liaison took place so most of them are the right age. I can't tie any of them specifically to being in Blackburn in 1928, but it's not out of the realm of possibility that they were visiting for some reason.

I'll have to do more digging, but does my basic logic seem sound? Is there anything I've missed, any flaws? Thank you so much

[Carmella]

Hi,

So from what you've posted it all seems to be logical.

As long as your 2nd biggest DNA match in your "Lancashire cluster" of shared matches is also of a decent size then I think you can be confident you've found the common ancestral couple.

Example - this tree posted on this thread:

https://www.rootschat.com/forum/index.php?topic=858148.0

Also different people DNA test with different companies so upload/ test with more than one company to increase the chances of solving your mystery.

[Romilly]

If you haven’t already done so,it’s worth uploading to Gedmatch:

https://www.gedmatch.com/

Plus, - I’ve found matches on the 23andme Site who haven’t tested or uploaded to any other Site.

Good luck, Romilly.