FamilyTree DNA have made two announcements in recent days:
1. Big Y-700 and Big Y Block Tree Matching Tool
Big Y-700 is an upgrade on the Big Y-500 DNA test. It is an improvement in terms of the amount of the Y-chromosome it covers, and the quality of the test itself. The increase in the number refers to the number of STR markers covered, and implies a 40% increase in coverage. However the real value of Big Y is the number of SNPs it uncovers. If this number is also 40% greater (something yet to be confirmed) then, on average, the time between SNPs down your patrilineal line will be reduced from 125 years to 95 years.
The price, at $645, is the same as for Big Y-500 which is now replaced. It remains to be seen whether the discounts in the next sale will bring the price down below $500 straight away. An upgrade from Big Y-500 will be made available later in the year. My impression is that this would only be useful in certain circumstances.
The Big Y Block Tree Matching Tool is a new way of visualising your position on FTDNA’s Y Tree. It is based on work done in the R-U106-S21 Project (both the Lancashire and Cheshire groups fall within this project). Anyone who has taken the Big Y test will appear on the Y Tree. For me it shows my most recent shared SNP is FGC17094. I share this and one other SNP with John Warburton, and we also have an average of 2 private variants. Further back I share SNP FGC17097 with Mark Warburton who has 4 private variants. FGC17097 is thus 5 SNPs back, so at an average of 125 years per SNP it occurred about 625 years before my birth, or circa 1320. This is the very year history states that William, son of Peirs Warburton by his second wife, and ancestor of Mark, was granted land in Partington.
The full announcement can be seen here.
2. Memo on Law Enforcement Access to Databases
There has been chatter recently about genealogical DNA databases being used to crack historical crimes, the most prominent being the unmasking of the Golden State Killer after crime scene DNA was submitted to genealogical DNA websites. A memo here from FamilyTree DNA President Bennett Greenspan explains the company’s policy on the subject. In essence FTDNA’s Gene-By-Gene laboratory has processed a handful of DNA samples for cold cases from the F.B.I. However law enforcement has the same access to the FTDNA database as any other ordinary user, unless under a valid subpoena or search warrant.
There are two things to note here. Firstly it took extensive research of the family trees of possible relatives to uncover a possible suspect, and this was only confirmed by surveillance, and direct DNA capture and testing. Secondly the activity seems to involve autosomal DNA databases, not the Y-chromosome used in the Warburton Project. However I can imagine Y-Tree matches could also be used to point investigators in the right direction.
My personal reaction is that FTDNA have struck a reasonable balance between their user’s privacy, which you control through your choice of options, and assisting the needs of law enforcement. Please read the full memo before forming a judgement.
Significance of Big Y and the Y Tree to the Warburton Project
Until this time last year you could only order Big Y as an upgrade to an STR test. That combined with the relative price made it logical to base the Warburton Project, like most other one name projects, on the Y-37 STR test. However when I saw the price of Big Y-500 in the recent sale was below $500, and compared that with the £400 I paid for my very first, limited DNA test, I realised that Big Y had to be a serious first option for some people.
In my post of January 2nd I described Big Y as the ‘test of choice’. In the rest of this post I shall expand that comment, identifying 3 types of test, and describing the best choices in different scenarios.
The objective of any DNA test is to find matches. The difference between STR matches and SNP matches is that SNP matches are definitive whilst STR matches are only indicative. My most recent shared SNP, FGC17094, like all SNPS, occurred once in a particular individual. My match John and I are his descendants. FGC17094 is at the end of a long list of SNPs which define our history. Others, like Mark Warburton, the Duttons and the Howells separate from this line at earlier stages. Another cousin, Clive did a specific SNP test for FGC17094, and was positive, proving he shared our history.
John and I had an earlier STR match. This indicated we had a common ancestor, but because STR mutations are bi-directional it was only the additional fact of our common surname that verified this. The test only indicated our earliest SNPs. The dates of common ancestors can be estimated from the genetic distance between two STR tests, and patterns of mutations can give some idea of when related clans diverged, but SNP sequences and matches give a more precise picture.
An objective of the Warburton Project is to show how related clans fit together. For the Lancashire and Cheshire groups, which share the six Big Y tests done so far, I have been able to produce haplotrees which define what we know so far about these relationships. The pictures are not complete. The Cheshire Group Haplotree is already linked from the DNA Project page. The Lancashire Haplotree will be added shortly.
In recent days I have been working on updating my DNA Project page and the main papers associated with it, to reflect the new situation. I will be publishing these updates soon.
If someone is considering a DNA test here are three options, Big Y-700, Y-37, and specific SNP tests.
Specific SNP tests rely on an indication of where a match might be, and a previous Big Y test to identify the SNPs to be tested. I usually use YSEQ.net for these tests, primarily because they have an option to Wish a SNP, or have a new SNP test created for a private variation.
To understand how these tests might be used I will describe a number of scenarios.
- Someone who is linked in a family tree to someone who has taken Big Y. This person will share the Big Y result so repeating it will add little value. They may wish to verify their link to the result with a specific SNP test.
- Someone in a clan which is linked to a clan where someone has taken Big Y. This person will also share much of the Big Y result, but they are likely to have an earlier shared SNP. A specific SNP test is more important to identify this shared SNP. However the earlier the shared SNP the more benefit will be obtained from another Big Y test. This will produce the new testers private variations which will make dating the shared SNP more accurate, and may become future branch points. Also the 700 STR results will provide a second mechanism for dating the common ancestor. In the Warburton Project only members of the Lancashire and Cheshire Groups fall into the first two scenarios. All others are in one of the scenarios below.
- Someone in a group of two or more clans linked by indicative (STR) matches. In this case there is no Big Y result to provide SNPs for comparison. A Big Y test is required to provide these SNPs. However the result of that test is of interest across all the clans, offering an opportunity for cost sharing. The new tester doesn’t have to be one of the original testers, though this might introduce the possibility of the mew tester being subject to a non-paternal event. Once the Big Y result is obtained members of the matching clans should then do specific SNP tests for the most recent shared SNP, and SNPs generated from the private variants.
- Someone in a clan that has an unmatched STR result, or matches contained within the clan. Here the best option is a Big Y test. There may be evidence that the original result was influenced by a non-paternal event. On the other hand it is possible a 700 year old Warburton clan is still quite small. Apparently over 90% of lines die out in the male line over 700 years, and very few grow to be large. The Big Y test may result in recent shared SNPs where the other parties have a different surname, giving a clue as to the origin of a non-paternal event. Or there my be no shared SNPs in the last 700 years ,supporting the case for an old but small clan. However future results might change the story.
- Someone who is in a clan with no DNA result, or isn’t in a published clan. In this case there are two options. A Big Y test will give a definitive result, but it just might turn out to be close to a previous Warburton Big Y result, and so provide little additional information. Starting with a Y-37 test might produce an indicative match, moving you into one of the above scenarios. A Y-37 followed by Big Y is a little more expensive than going straight to Big Y, but if a Y-37 can be followed by a few specific SNP tests it would be a lot cheaper.