[davecap1]

23andMe only tests for known relatively common mutations (single nucleotide polymorphisms, or SNPs) that have been identified by non-profit large scale sequencing projects done in the past (basically public data now, see dbSNP for instance). You will almost certainly have mutations that are not covered by their panel, so it is not a matter of comparing your 23andMe results to the "baseline" (or "reference genome"). Their panel costs in the hundreds of dollars to run since it is so focused (at least 10x less than a full "exome" test, which would look at the full sequence of all known genes).