The 856 genotyped CNPs represent an average of 3.5 megabases of sequence in each individual; this is ≈0.1% of the human genome, and similar to the overall rate of SNP variation. One-third (33.5%) of the genotyped CNPs overlap RefSeq genes, with duplications more likely than deletions to overlap genes (after correcting for the greater average length of duplications (P = 0.006)), which probably reflects greater purifying selection acting on deletions of genes.
