Terry has noted that Cunningham Lineage III has a characteristic marker—namely DYS425=0. I’ve been investigating what this means and how it comes about, and thought I’d share a summary with the list. Lineage III members also share another set of characteristic marker values that I’ll get to below.
When the lab reports a zero count for a marker, it means that the test didn’t detect the marker at all. This is the result of a mutation in the region next to the section of repeats, where one of the primers binds to the DNA, selecting the region to be analyzed. The mutation prevents the primer from attaching, and the test produces no result. The lab always repeats the test if a null result is read the first time, in case something else went wrong. The pair of null results amounts to detecting the presence of a mutation of some sort.
There is an advanced test available, DYF371X, that detects which base (C or T) is present in the DNA at the position where the DYS425 test expects to find T. DYF371 is a multi-copy marker, and results at all positions (usually four) are reported, both the repeat count and the base present. If you tested Null at DYS425, and are curious enough to order the DYF371X test (cost is just under $20), you are eligible to join the Null425 Project at FTDNA. Look at the information pages at that project for more reference material on the whole subject. See http://www.familytreedna.com/public/null425
In addition to the 425=0, Cunningham III members share a set of marker values that place us in a cluster identified by Mike Maddi , that he calls Null425/S21+. Unlike the overall Null425 group, who seem to be of any haplogroup, and therefore not related, this cluster are all projected to be R1b1 or R1b1c. All who have SNP tests are S21+, or haplogroup R1b1c9. Characteristic markers are 425 = 0, 492 = 13, and at least 2 out of 3 of 390 = 23, 447 = 24, and 460 = 10. Where the right markers are tested, all of the Cunningham III group have them all. These values are fairly rare, so the combination is unusual. Mike’s cluster has fewer than 40 names, with three Cunninghams and one Cummings. Everyone in Cunningham III would be included if your haplotypes had been entered into Ysearch.
Mike has posted a link that brings up a ySearch page showing the members of the cluster at with 66 markers:http://tinyurl.com/2qz5bg