I have asked questions about this before but here I am asking again. My Father's ydna haplogroup/type has been categorized by one testing facility as just "I", yet when he had a 2nd test done several months later that offered a specific market needed to determine Norse ancestry, their results came back that he was "I1a".
The first testing facility did an SNP test on my Father and it came back as P19, however I noticed in the SNP charts online that I's are M170, M258 and P19, while I1a's are M253, M307 and M30 (I hope I have that correct).
Does this mean that the first testing facility only checks certain areas and that the other one checks certain areas that differ from each other?Or are SNP's determined by the number of markers tested?
Also, I have noticed that others that have tested the same amount of markers as my Father did with the First Testing facility, their Haplogroup was listed as I1a rather than I. What determines the difference and why was my Father's haplotype not listed by the First company as I1a when the 2nd one did?
I am confused by this, and on what is an SNP result based on? How do they arrive at those numbers? Thank You