I have tested at both 23andme (V3) and AncestryDNA. I have written a program to add the raw data file information into a MySQL database, creating separate tables for my 23andme results and my AncestryDNA. I am trying to understand some things. First, some of the terminology that 23andme uses in its raw data file. Here is a list of distinct SNP pairs: +------+ | PAIR | +------+ | -- | | A | | AA | | AC | | AG | | AT | | C | | CC | | CG | | CT | | D | | DD | | DI | | G | | GG | | GT | | I | | II | | T | | TT | +------+ I can understand all the A, C, G, T lettering. The single letters represent SNPs on my Y and X chromosomes. I also understand that '--' is a no call. What are 'DD' and 'II'? I also found that AncestryDNA had no 'AT' SNPs for me, but 23andme had 611: mysql> select COUNT(*) from ANC WHERE PAIR = 'AT' ORDER BY PAIR; ----------+ COUNT(*) | ----------+ 0 | ----------+ row in set (0.07 sec) mysql> select COUNT(*) from 23andme WHERE PAIR = 'AT' ORDER BY PAIR; ----------+ COUNT(*) | ----------+ 611 | ----------+ Can anyone explain why I have no 'AT' SNP pairs in my AncestryDNA raw data file? I verified this by browsing my Ancestry Raw data file. I had every other SNP pair represented. The final question is about RSIDs. What are the ones that begin with 'i' in my 23andme raw data file? I have 10,709 RSIDs that begin with 'i-----'. David