A great blog post written by Maurice Gleeson almost a year ago calling for the term 'NPE' (Non-paternity Event or Not Parent Expected) to be referred to as Surname or DNA Switch, 'SDS'. The blog is great at explaining the possibilities and probabilities of this occurring.
For a Doherty tester born in 1950 there is 31 – 52.5% of a SDS occurring in their patriline across 37 generations to what is believed to be the progenitor common ancestor of 850 – 900 AD. (continue reading for the math involved).
His probability calculations on this occurring is based on several conservative estimates from various studies of 1 – 2% per generation. Note that he calculated this incorrectly with a correction in the comments.
For Ó Dochartaigh if we are to assume that Group 1 testers descend from the progenitor of the first man to earn the title "Dochartaig" then the testers are estimated to converge at around 850-900 AD.
If we have a male Doherty (or variant spelling) tester born around 1950 then, on average assuming 30 years per generation, there would be approximately 1,100 years to this progenitor or ~37 generations.
So, the calculation for a 1% per generation would be:
0.99 ^ 37 = 0.6894
which is stating there is a 68.9% chance this Doherty tester DID NOT HAVE AN SDS on his line, or, in other terms, there is a 31% chance this tester's patriline experienced an SDS.
Same calculation for 2% would be:
0.98 ^ 37 = 0.4735 or 47.4% of no SDS, in other terms 52.6% probability of and SDS occurring across 37 generations.
So, a male tester born in 1950 would have a 31 – 52.5% chance of a Surname or DNA Switch on their patriline across 37 generations or approximately back to 850 AD when Group 1 Dohertys converge on a common ancestor.
Everyone likely received emails on the Father's Day Sale for 2019. Sale ends June 17th. Be sure to consult an administrator if you have questions on testing.
An infographic produced by Dave Vance that is helpful on describing private, unnamed and shared variants for SNP discovery.
For those interested the DNA Day Sale at Family Tree DNA has been extended through April 28 (midnight PST).
For those interested in upgrades but are unsure of what further testing please feel free to email me. Email address is to the left of this activity feed.
It appears there were codes for upgrades from various levels. Here those are. Again, these all end March 31.
*Note: The Big Y discount of $200 only applies to a Big Y ordered from scratch; meaning a Big Y on an account with no prior STR testing having been performed.
For all those that had performed a Big Y that later was converted to Big Y 500 (this conversion didn't require running a new test, instead it was simply remapping the already tested data to a new human reference genome) and that have voiced interest in upgrade to Big Y-700 which is a new test and requires a new test to be performed.
News at the FTDNA conference this last weekend is that the upgrade from 500 to 700 costs users $179.00 until March 31st (this month). I've only heard it rumored that the upgrade price will move up to $249.00 after this.
Things to note:
- I don't necessarily recommend this upgrade to previous Big Y-500 users. The advantages of this new test are not the additional and somewhat useless STRs (useless because they are very slow mutating STRs). The clear advantage is the increased coverage of the Y chromosome which is resulting in more SNPs discovered per number of generations. This provides more granularity in breaking potential matches down further. This can be helpful in a group of Big Y testers that formed a clade but suspect they may be more closely related to only a subset of those testers.
- This test won't discover new matches. What I mean by this is that if two testers weren't relatively close matches to one another on Big Y-500 they won't all of a sudden be close matches after a Big Y-700.
- Average SNP/year on Big Y-500 was 1 SNP for every 131 years in a line. New Big Y-700 with increased coverage is averaging 1 SNP for every 82 years in a line. See the statistical breakdown between the two and other NGS tests here: https://ydna-warehouse.org/statistics.html
I'm open to any questions people may have on this. Note that I didn't personally attend the conference but have been keeping up on the information being reported.
I just wanted to point to people this new website and excellent resource that Will Dougherty III (B2905) put together of his own free time and interesting in everything Ó Dochartaigh. It has tons of historical information on the surname. You can find the website here:
In light of recent news I thought I would re-share the link to the letter that Bennett Greenspan, CEO of FTDNA sent out to everyone (can read the full letter here: https://mailchi.mp/familytreedna/letter-to-customers?e=f7f0388e87).
There are a lot of sensationalized headlines floating around that the FBI have the "Keys to the Kingdom" with regards to all our data. These headlines are grossly inaccurate. What is occurring is that the FBI, like any customer, can submit a sample to FTDNA as any of us can in cases of Jane/John Does that they do not know the identities to and/or samples from violent crimes. Once doing this Law Enforcement have to do the the same thing we customers do in determining a common ancestor based on the matches to their samples and then work their way down to who the sample may belong to using the same genealogy methods we employ on discovering our ancestry. They do not have special tools or access in doing this, it is the same level access each of us have. Quite honestly the FBI could submit samples to any of these databases (Ancestry, 23andMe, MyHeritage, etc.) without even letting the company or its customers even know.
This being said the Doherty Project has no one leave so far. Out of the 5 surname projects I voluntarily administer totalling over 2000-3000 people, there has been only one case of a person leaving and their reason appeared that they had a large misconception on what FBI can access.
I'd be happy to discuss any concerns or answer an questions anyone has with regards to this. Keep in mind I'm not an employee of Family Tree DNA. Just a customer like everyone else here with an extreme enthusiasm for leveraging genetic genealogy to help validate and build family trees and connections.
All the best,