 Living organisms use solely RNA primers, while laboratory techniques in biochemistry and molecular biology that require in vitro DNA synthesis (such as DNA sequencing and polymerase chain reaction) usually use DNA primers, since they are more temperature stable.RNA primers are used by living organisms in the initiation of synthesizing a strand of DNA.A class of enzymes called primases add a complementary RNA primer to the reading template "de novo" on both the leading and lagging strands.