The two groups that published the draft sequence of the human genome last year used different experimental strategies. The public Human Genome Project used a hierarchical shotgun (HS) approach, whereas Celera Genomics chose a whole-genome shotgun (WGS) strategy. In the Early Edition of the
Celera assembled the draft sequence using experimental, random shotgun data and sequences from the HGP database that had been artificially 'shredded' into short fragments. Robert Waterston, Eric Lander and John Sulston suggest that this shredding exercise generated a 'perfect tiling path' with few gaps, which is far superior to that generated from random sequences of equivalent or greater coverage. It is therefore difficult to assess the contribution of the...