Genetic material (3)
'genetic material' is the definition.
(I've seen this in another clue)
This is all the clue.
(Another definition for rna that I've seen is " Messenger".)
(Other definitions for dna that I've seen before include "It carries genetic information" , "Substance in chromosomes that stores genetic information, used by police" , "Genetic-code molecule" , "Main constituent of chromosomes" , "Substance in chromosomes that stores genetic data" .)