the first thing i have to do is take the tune and i get to fill it with slief hav splie saliva.an watch me spit. that's done. i joined 23 million people who sent their saliva to 23andme. to conduct a personal dna test. they begin with our 46 chromosomes, 23 from each parent, filled with you're dna. dna is a double helix with base pairs of nucleotides. as paired with cs. >> katy: , g s.over and over. so that a sequencing machine has enough material to determine the exact order of those as ts gs and cs. >> that's the instruction manual for what makes you you, and me me, and other people themselves. when we sequence dna, we are determining the order of those bases then you match them up to a reference. you match up to where you differ from the reference sequence. and those changes are what are used to predict what might go wrong with you . 23andme is a conglomeration of: know more about your health. go to 23andme and order your dna kit for only $99 today. >> with the fine print, "not a substitute for professional medical advice," in november of twean. 2003. 2013 . >> the underlying