on resequencing samples from the initial and extended HapMap populations from around the world. Even with new sequencing techniques, this is a monumental effort. However, it is still likely to be only a first installment. To reliably determine the pathogenicity of rare variants as they are identified, we will probably need reference sequences from tens or hundreds of thousands of subjects, coupled with a better understanding of the biologic effects of SNPs. Housing and making accessible such data will be a considerable challenge, especially when one considers that the data will include variants pertaining to both SNPs and structural genomic variability.
