Like DNA, RNA is a complex molecule made of repeating units of thousands of smaller molecules called nucleotides that link together in very specific, patterned ways.

Its biochemistry would work just like ours-dna to RNA to proteins-but it would be completely incompatible with earthly life, its chiral twin.

Secondly it must have been able to quickly assemble a genetic molecule that could make copies of itself without the need for more elaborate bio-machinery like RNA and DNA -- that would evolve later.