R-DF21 and Subclades - Results

In regard to L459, the problem is with the way FTDNA reports null alleles. FTDNA is reporting my result as L459-, but the result was actually ambiguous, meaning there was no result. FTDNA reports these as ancestral (-), by FTDNA convention. 

An ambiguous result can occur for many reasons, but after a brief discussion with Thomas, the most likely culprit is an SNP at or near the primer locus preventing it (the primer) from binding. 

I believe FTDNA ran L459 for me 8 times and all failed; FTDNA will not continue to test ad infinitum as whatever the condition that exists that was preventing this segment from being read is still present, and any additional testing with the same primer will almost certainly fail as well. 

161731 has a regular haplotype without any visible deletions, therefore I'd guess it is some local point mutation that prevents the primer from binding. He is the only L459 Null I know of.