Using random priming to obtain full-length V(D)J information for immune repertoire sequencing

A method for labeling nucleic acid targets in a sample, comprising:

• contacting copies of a nucleic acid target with a plurality of oligonucleotide barcodes, wherein each oligonucleotide barcode comprises a first universal sequence, a molecular label, and a target-binding region capable of hybridizing to the nucleic acid target;
• generating a plurality of barcoded nucleic acid molecules each comprising the target-binding region and a complement of the target-binding region;
• hybridizing the complement of the target-binding region of each barcoded nucleic acid molecule with the target-binding region of one or more of:
• (i) an oligonucleotide barcode of the plurality of oligonucleotide barcodes,
• (ii) the barcoded nucleic acid molecule itself, and
• (iii) a different barcoded nucleic acid molecule of the plurality of barcoded nucleic acid molecules;
• extending 3′-ends of the plurality of barcoded nucleic acid molecules to generate a plurality of extended barcoded nucleic acid molecules each comprising the first molecular label and a second molecular label;
• amplifying the plurality of extended barcoded nucleic acid molecules using a target-specific primer capable of hybridizing to a sequence of the nucleic acid target and a primer comprising the first universal sequence, thereby generating a first plurality of barcoded amplicons comprising the sequence of the nucleic acid target, or a portion thereof;
• and
• hybridizing random primers to the first plurality of barcoded amplicons and extending the random primers to generate a plurality of extension products.