Please note, for oligonucleotides containing redundancies SGS DNA do not take responsibility for the product having an even distribution of the different nucleotides. In case of more than four redundancies we cannot guarantee any purity requirements.

Randomized oligonucleotides

I recently ordered an unmodified 20-mer containing one redundancy (A/G). The enclosed HPLC chromatogram shows two peaks. How come?

Due to the redundancy, your product contains two variants of the sequence- one variant containing A and the other variant containing G in the redundant position. When your product is analyzed by AIE-HPLC, the retention time for these two variants varies and therefore they are shown as two peaks.

I am interested in a randomized oligonucleotide. The oligonucleotide is randomized in 6 codon and is 157 bases long. Is this possible? What is the maximum length on such oligonucleotide?

Yes, we can manufacture such oligonucleotide. However, please note that we in your case cannot guarantee that all possible variants are present in your oligonucleotide, due to the great number of randomized positions. The maximum length of an randomized oligonucleotide varies with the base composition but are normally somewhere between 150 and 200 nucleotides.