DNA and RNA genetic material. There are some differences between them. DNA is deoxyribonucleic acid. RNA on the other hand is ribonucleic acid. Although DNA has two polynucleotide chains, RNA has one chain. DNA is always double-stranded, but RNA is mostly single-stranded. The pyrimidine base of DNA is cytomine and thysin. The pyrimidine bases of RNA , on the other hand , are cytosine and uracil. DNA can replicate itself but RNA cannot.