I am posting this in the hope that someone will either confirm my theories or tell me that I am completely wrong. If I share a single 3 cM segment of DNA with someone, then there is a 97% probability that it is due to random factors. Turning it round, there is only a 3%…
All posts tagged DNA
Looking for faint stars
It seems that most of the DNA evidence that I have at present is like trying to identify very faint stars on a dark night. You know that they are there, but you cannot be certain exactly what you are seeing. Is it a star, or a figment of your imagination? We want to discover…
Power of numbers
I am a member of the Roscommon DNA Facebook group. At the time of writing (April 2022), there are over 1,100 members. There are 1482 samples that can be cross checked on Gedmatch.com. (Some members manage samples on behalf of other people.) If I run the analysis on Gedmatch, with a minimum cut off of…
Who was Bridget Scott?
In ‘Ormsby & Scott’, I explained the dilemma about the identity of my great grandmother Bridget. The birth record of the sister, Mary, with whom Patrick is staying in 1911 clearly names her mother as Bridget Ormsby. Patrick’s birth records from March 1883, both civil and church, name his mother as Bridget Scott. Are we…
How far back?
In the ‘Dewsbury once more’, I referred to the identification of a common ancestor. The other researcher and I share 95 centimorgans of DNA. We are third cousins once removed. The point at which our family trees coincide is John Stanley, born sometime around 1800. His date of birth could be as late as 1807.…
95 centimorgans
This blog explores the opposite problem to the previous one (Multiple clans). https://www.roscommonstanley.me.uk/geography/ireland/multiple-clans/ Ancestry has identified someone with whom I share 95 centimorgans (cM) of DNA. (Other testing companies are available!) This is by far the highest score that I have on my list. The next highest is 51. According to the wonders of the…
Multiple clans
When I started out on this voyage of exploration, in 2007, I knew almost nothing about my grandfather’s origins. I have discovered a lot in the meantime. I have files full of information. Perversely, there now seems even more that I don’t know. This is where you need to check out Donald Rumsfeld. In 2002,…
Both ends to the middle – Part 2
Part 1 was really an extended preamble. How do the principles apply to ‘the man in the street’? We have to move from the known to the unknown. What information do we have with which to start? We might have locations. Ideally these are Townlands, because they are the smallest unit of area, often with…
Both ends to the middle – Part 1
In April 2019 I posted a blog on my family history website entitled “DNA: the magic bullet?”. (https://www.roscommonstanley.me.uk/direct-line/dna-the-magic-bullet/ ) In the intervening period, the number of DNA matches that appear on my list from Ancestry has expanded. In the 4th-6th cousin group (above 20 cM of DNA in common) there are 294 names. I refer…