 DNA phenotyping uses many of the same scientific methods as those being used for genetically-informed personalized medicine, in which drug responsiveness (pharmacogenomics) and medical outcomes are predicted from a patient's genetic information.Significant genetic variants associated with a particular trait are discovered using a genome-wide association study (GWAS) approach, in which hundreds of thousands or millions of single-nucleotide polymorphisms (SNPs) are tested for their association with each trait of interest.Predictive modeling is then used to build a mathematical model for making trait predictions about new subjects.