NanoString Technologies, the Seattle-based maker of tools for genetic analysis, said today it has introduced a new product to analyze microRNA molecules on its nCounter instrument. MicroRNAs are tiny strings of RNA that don’t carry the instructions for making genes, but are thought to regulate the activity of important biological processes. NanoString is rolling out the new application to coincide with the annual meeting of the American Association for Cancer Research in Washington D.C., where a number of enthused microRNA researchers are gathered today. NanoString primarily sells its instrument to researchers who want to look at how genes are dialled on or off in a sample, and it also foresees using the technology as a diagnostic tool.