Dan Koboldt at MassGenomics explains why exome sequencing often fails to identify causal variants, even in Mendelian disorders — "the very plausible possibility that a noncoding functional variant is responsible."
Koboldt, the analysis manager in the human genetics group at the Genome Institute at Washington University, says that researchers shouldn't overlook the importance of noncoding functional variants, which require a suite of technologies to detect, including RNA-seq, ChiP-seq, DNAse sequencing and footprinting, bisulfite sequencing, and chromosome conformation capture.
"These types of experiments generate a wealth of data about regulatory activity in genomes," he says. "While studying each of these independently is certainly informative, integrative analysis will be required to elucidate how all of these different regulatory mechanisms work together."
While this effort will require "robust statistical models, substantial computing resources, and productive collaboration among research groups, the end result "will be a far more complete understanding of how the genome works," he says.