SNP P66+, which I had hoped to use to identify a specific Maguire ancestor is not
a reliable indicator according to Thomas Krahn, head of FTDNA's Houston lab.
A Maguire who was P66+ long ago can well have sons several generations later
who would be P66- and that is the problem with Recloh events. These act more like
STR's (Short Tandem Repeats) also called alleles or markers than like SNP's
(Single Nucleotide Polymorphisms). The practical difference to those like me
who don't understand this scientific stuff, is that STR's generally show family
history back to about 200 years before surnames came into common usage whereas
SNP's generally go back, way, way back thousands of years. For example, Niall
of the Nine Hostages has SNP M222+ but SNP M222- goes back four thousand
years ago while M222+ only goes back 3,000 years ago.
Meanwhile, cousin, Sam, is now upgrading to 111 markers, having his deep sub-
clades (SNP's) tested plus SNP's L513 and L69. If all goes as expected, he will
also be P66+, L513+ and L69+. Brad McGuire, adm. of the FTDNA Airghialla
Mag Uidhir (Maguire) group that is based both on surname and geographical
origin, can now predict who will have Maguire DNA and who will not based on
six markers and from those can predict which SNP's an individual will + or -.
This reminds me of why I enjoyed history classes that dealt with battles fought and
wars won or lost but totally lost interest when it came down to economic history.