ncRNA is transcribed from DNA, but not translated into protein. It often plays a regulatory role. Some probably most ancient ncRNAs encompass catalytic functions and are called ribozymes (e.g. RNaseP). Others are tRNAs and ribonucleoprotein complexes such as rRNA within ribosomes or snRNPs of spliceosomes. Others function as RNA templates within telomerase which is related to reverse transcriptase.