—Direct RNA Sequencing “Helicos BioSciences reports a method for direct RNA sequencing that avoids first converting RNA to complementary DNA” RNA sequencing usually requires an indirect approach of converting the RNA to complementary DNA and then sequencing that DNA. This cDNA approach doesn't work well for RNA samples that are short, degraded, or available in limited quantities. Now, scientists at Helicos BioSciences, in Cambridge, Mass., report a method for direct RNA sequencing (Nature, DOI: 10.1038/nature08390). Patrice M. Milos and coworkers extend the company's single-molecule DNA-sequencing methods by incorporating a polymerase that can use RNA as its template. The target RNA molecules are arrayed on a planar surface, and their sequences are determined by synthesizing the complementary strand through repeated additions of nucleotides with fluorescent labels and cleavable inhibitors that block the addition of other nucleotides.
by Celia Henry Arnaud |
September 28, 2009