Accurate molecular barcoding

According to some embodiments herein, compositions and methods for accurate barcoding of nucleic acids are described. The compositions and methods involve a plurality of unique oligonucleotide species comprising unique molecular barcodes. Molecular barcodes have a relatively low G (guanine) content, for example, each of the barcodes contains less than 50% guanine or the total set of barcodes contains on average less than 12.5% of guanine. The barcode array is intended to show reduced bias in amplification and analysis. (Automatic translation with Google Translate, without legal value)