I am regularly asked - how many yDNA markers should I test?
My standard response is to buy your yDNA test through your surname project at FTDNA and to "start with either 37 or 67 markers".
Let's break this response into pieces:
1. FTDNA dominates the yDNA testing for genealogy - hosting almost all of the Surname DNA Projects. If you test anywhere else - you will be trying to join your test results to your surname project once you understand that a surname project really is where you need to work to find your matches. (there are a few exceptions - which I will discuss in another blog entry)
2. Test through your surname project (you may have a variation of the banner name - but that is ok). There are a couple of reasons for this: One, most men match others with their surname. Two, you should receive help from your project administrator simply by being in the project. Three, even if you are matching a different surname(s), you still want to have your results in your own surname project. (you can also join the project(s) of the men you match)
3. 37 markers is the minimum number of markers when you are comparing to other men when you have no paper trail connection to them. Often, you'll need to upgrade to 67 or even 111 to discern which of your matches is relevant. (This seems to happen most often for those with Irish descent - as many men have very similar profiles)
4. A 12 marker test has a couple of useful purposes: One, you can confirm that you DO NOT share recent common ancestry with a family suspected of being your kin. Two, you can usually confirm if you share ancestry with a man who has a paper trail that connects closely to you. Three, you can store (for 25+ years) the DNA sample of a male family member. HOWEVER - it is NOT APPROPRIATE for a man testing to seek to find his unknown kin with a 12 marker test. That requires AT LEAST 37 markers
5. A 25 marker test is foolish in nearly all circumstances. (Don't buy this test unless your project administrator specifically recommends that you buy it) You save only $25 vs a 37 marker test and it will cost you $49 to upgrade from 25 to 37 markers.
6. 67 yDNA is becoming the standard for many researchers. It's pretty likely that you will want to be tested to this level after you start looking at your matches. However - if all of your matches are only tested at 37 markers and the connection is clear - 37 is enough. If you need more markers, you can order an upgrade to 67 which will reuse your initial sample. It's a tradeoff between cash flow and time whether you start at 37 or 67 - and there is also the issue of whether you have matches tested only at 37 - or whether 67 or 111 is the norm for the men you match.
7. 111 yDNA is the largest standard test today. This is my personal choice - but only until a larger standard test is available. (I believe we need even more than 111)