DNA Library Preparation Anti-Contamination Adapters

The patent applies preliminary action by adding sample-specific index sequences to adapters during the adapter ligation step (early stage) rather than waiting until the final PCR step. This early tagging allows each sample to be uniquely identified throughout the workflow, enabling multiplexing without cross-contamination risks. The index sequences are incorporated into the adapter structure itself, so samples are separated virtually from the beginning of the pooled library construction process.

The patent uses index sequences as informational copies that tag each sample with its identity. These index sequences are incorporated into the adapter molecules during ligation, creating a permanent record of sample identity that travels with the DNA fragments through all subsequent processing steps. This allows automated equipment to handle pooled samples without risking cross-contamination, as each fragment carries its own identification code.

The patent segments the adapter design by incorporating distinct index sequences into the adapter structure. Instead of using a single universal adapter, the system uses multiple adapter variants (A, B, C, D pairs) each with unique index sequences. This segmentation allows samples to be differentiated and tracked individually while still using the same fundamental adapter ligation chemistry, maintaining procedural simplicity while enabling robust sample separation.