Method of determining a ratio of rna species in a sample

A method of determining a ratio of RNA species in a sample, the method comprising:

• providing a sample comprising two or more different RNAs;
• incubating the sample in the presence of an enzyme that converts the 5′-cap structure into 5′-monophosphate to convert RNA having a 5′-cap structure into RNA having 5′-monophosphate;
• incubating the sample in the presence of an enzyme that phosphorylates 5′-OH to convert RNA having 5′-OH into RNA having 5′-monophosphate;
• incubating the sample in the presence of an enzyme that dephosphorylates a 3′-end to convert RNA having a 3′-phosphate group into RNA having 3′-OH;
• incubating the sample in the presence of RNA ligase to produce circular RNA;
• incubating the sample in the presence of RNA-dependent DNA polymerase to produce DNA from the circular RNA;
• identifying the produced DNA;
• and
• determining a ratio of RNA species in the sample from the identified DNA.