I want to clear up a misconception here. Odds are that for $100 you didn't get any sequencing done. More likely they used a genotyping chip to look for (potenti

I want to clear up a misconception here. Odds are that for $100 you didn't get any sequencing done. More likely they used a genotyping chip to look for (potentially a lot) of specific variants. This is what 23andMe does. The price of sequencing the exome (all of the genes in the genome) is approaching $100 and could be lower than that for really high volume producers, but for now the most common assay at that price point is a chip.