Non-coding RNA genes include highly abundant and functionally important RNAs such as transfer RNA ( tRNA ) and ribosomal RNA ( rRNA ) , as well as RNAs such as snoRNAs , microRNAs , siRNAs , snRNAs , exRNAs , and piRNAs and the long ncRNAs that include examples such as Xist and HOTAIR ( see here for a more complete list of ncRNAs ) .
Non-coding RNA genes include abundant and important RNAs such as transfer RNA ( tRNA ) and ribosomal RNA ( rRNA ) ; also RNAs such as snoRNAs , microRNAs , siRNAs , snRNAs , exRNAs , and piRNAs and the long noncoding RNAs ( long ncRNAs ) .