>It also sounds like it's not random-access either.
Read the article again!
We propose a method for random access that uses a polymerase chain reaction (PCR) to amplify only the desired data, biasing sequencing towards that data. This design both accelerates reads and ensures that an entire DNA pool need not be sequenced.
We demonstrate the feasibility of our system design with a series of wet lab experiments, in which we successfully stored data in DNA and performed random access to read back only selected values.