Abstract: A series of hybridisations is performed for forming a target double-stranded nucleic acid from initial fragments, where each further hybridisation step hybridises the direct products of a pair of earlier hybridisation steps. For at least one further hybridisation step HF, both of the corresponding pair of earlier hybridisation steps HE comprise an error-detecting type of hybridisation step, which includes an error detecting operation to detect whether the hybridised fragments formed in the error-detecting type of hybridisation step HE comprise at least one erroneous hybridised fragment, and discarding at least part of the erroneous fragment to exclude it from a subsequent further hybridisation step. By detecting and removing erroneous fragments throughout a staged and controlled hybridisation process, erroneous fragments are prevented from diluting the pool of error-free fragments at each hybridisation step, to improve yield.

Abstract: A series of hybridisations is performed for forming a target double-stranded nucleic acid from initial fragments, where each further hybridisation step hybridises the direct products of a pair of earlier hybridisation steps. For at least one further hybridisation step HF, both of the corresponding pair of earlier hybridisation steps HE comprise an error-detecting type of hybridisation step, which includes an error detecting operation to detect whether the hybridised fragments formed in the error-detecting type of hybridisation step HE comprise at least one erroneous hybridised fragment, and discarding at least part of the erroneous fragment to exclude it from a subsequent further hybridisation step. By detecting and removing erroneous fragments throughout a staged and controlled hybridisation process, erroneous fragments are prevented from diluting the pool of error-free fragments at each hybridisation step, to improve yield.