We do not use restriction enzyme based cloning. Please do not include any extra nucleotides in your inserts in anticipation of Restriction Enzyme digestion followed by DNA ligation. When you place an order for a clonal gene, we synthesize exactly the insert sequence you send us. If you do include flanking Restriction Enzyme sites, we will synthesize those, too; extra base pairs are not excised. The insert sequences are not processed in any way once they are received.   If you are placing a clonal gene order using a Twist or Custom Vector, we highly recommend that you double check the sequence of the final construct using the Download sequences button in the designer: Please note that once a gene order has been placed, we cannot alter the sequence in any way - if you discover an error in your construct, please contact customersupport@twistbioscience.com for assistance.