Only two surnames have currently tested positive for L563: Creer and Nuckolls. Many other surnames should also test positive as well: McKenzie, Mills, Lebbetter and probably several other surnames. There are around 20 Creer submissions found at the Creer Surname project. Unfortunately, only two submissions have been tested at 67 markers - both have tested positive for L563. This surname has an unusual geographical tie to the Isle of Man (an island between England and Ireland).
The MRCA for L563 is 14 mutations from the MRCA of R-L21. With the recent positive test of the Nuckolls submission (181546), the L563 fingerprint could lose an additional five markers which would greatly expand the scope of L563. The best testing candidates for L563 are:
1) There are 20 Creer submissions that are very good testing candidates. None of these submissions are 67 markers or higher and need to be upgraded before testing for the L563 Y-SNP. The fingerprint of L563 is probably too narrow until more submissions are tested. There are two McKenzie submissions, two Mills submissions and one Ledbetter submission that have pretty high odds of testing positive. If multiple submissions descend from the same oldest proven ancestor, only one submission needs to be tested for L563 per genealogical line.
2) There are 30 additonal submissions that match 8 of 14 markers of the Creer fingerprint. Markers not matching L563 fingerprint 385a, 464b, 576, 413a and 487 should discount these misses as several of these markers will probably not survive as part of the L563 fingerprint after additional testing. Only 20 to 30 % of these submissions will test positive since the L563 fingerprint is not well known with the recent Nuckolls positive test.
3) Even 7 of 14 matches could test positive but these are more speculative since the L563 will definitely undergo more modification with more testing. These submission probably have only a 10 to 15 % chance of testing positive. Again, for the five markers listed above, if these makers do not match vs. other markers, then the odds for testing positive goes up.