Such changes could include wholesale deletions of chunks of the genome or additions of extra copies. Cancer genomes, in particular, mutate rapidly and contain frequent abnormalities.
"That's something that's very hard to detect" by conventional sequencing, Green said, adding that sequencing can simply miss part of a genome.
Optical mapping, by contrast, can estimate the absolute length of a genome and quickly detect differences in length and structure between two genomes. Comparing optical maps of healthy and diseased genomes can guide researchers to crucial mutations.
Though he called optical mapping "potentially very powerful," Green added that it requires such a high level of expertise that only a couple of laboratories in the world use the method.
The Waterman group's algorithm may encourage others to take a second look.