Sequencing of nucleic acids via barcoding in discrete entities

A method of introducing multiple copies of a first nucleic acid barcode to nucleic acids of a discrete entity, the method comprising:

• encapsulating a plurality of nucleic acid target molecules in a discrete entity;
• flowing the discrete entity in a first channel to a junction;
• flowing a continuous, unsegmented reagent flow comprising multiple copies of a first nucleic acid barcode and multiple copies of a second nucleic acid barcode in a second channel to the junction;
• flowing a carrier fluid in a third channel to the junction, wherein the second channel comprising the continuous, unsegmented reagent flow is positioned between the first channel comprising the discrete entity and the third channel comprising the carrier fluid;
• merging the discrete entity into the continuous, unsegmented reagent flow downstream of the junction;
• and
• downstream of the junction, inducing the continuous, unsegmented reagent flow to break off one individual microdroplet comprising the plurality of nucleic acid target molecules of the discrete entity, multiple copies of the first nucleic acid barcode, and no copies of the second nucleic acid barcode, such that substantially all of the plurality of nucleic acid target molecules of the discrete entity are broken off into the one individual microdroplet.