Final answer:
Barcoding in Illumina sequencing refers to the process of assigning unique DNA sequences to multiple samples to identify and differentiate them, enabling high-throughput and multiplexed sequencing runs.
Step-by-step explanation:
When referring to Illumina sequencing and barcoding, the correct answer is a) Assigning unique DNA sequences to samples. This technology utilizes barcoding to label different DNA samples with unique sequences, which allows for the simultaneous processing of multiple samples. This method is imperative in distinguishing between different specimens, even among highly similar ones, or in identifying unknown species by comparing barcoded regions to known sequences.
Barcoding is especially useful in high-throughput sequencing techniques like those developed by Illumina, where multiple samples can be sequenced together, and later, the generated data can be sorted based on the barcodes. This efficient workflow is crucial in various applications such as comparing samples of ancient DNA with modern organisms, determining the presence of unculturable microorganisms, or conducting forensic analyses.