I had a colleague ask me recently whether mRNAs could be sequenced directly. I found this Nature paper published by Helicos in 2009, in which they describe their developments in the area. It's been several years since this was published, and yet RNAseq and most other transcriptomic analysis is still done by first reverse transcribing RNA into complementary DNA.
What is the current state of RNA sequencing? Has Helicos failed to deliver on their technology? Have any other platforms risen to the challenge (or attempted to do so)? Or is the technology successfully in production and still simply overshadowed by the wide adoption of traditional cDNA-based sequencing methods?