This invention provides methods of altering a cell including providing the cell with a nucleic acid sequence encoding a Cas1 protein and/or a Cas2 protein of a CRISPR adaptation system, providing the cell with a CRISPR array nucleic acid sequence including a leader sequence and at least one repeat sequence, wherein the cell expresses the Cas1 protein and/or the Cas2 protein and wherein the CRISPR array nucleic acid sequence is within genomic DNA of the cell or on a plasmid. Also provided are methods and systems for nucleic acid storage and in vivo molecular recordings of events into a cell.