title: DNA-Seq of white cell
design: Next Generation Sequencing (NGS) library preparation is a critical step in the sequencing workflow that involves preparing DNA or RNA samples for high-throughput sequencing. The basic steps of NGS library preparation include fragmentation, end repair, adapter ligation, amplification, and quality control. Here's a simplified overview of these steps:1. **Fragmentation**: DNA is broken into smaller fragments of uniform size to create a library with manageable read lengths for the sequencer. This can be achieved through enzymatic digestion or physical methods like sonication.2. **End Repair**: Fragmented DNA ends are repaired to create blunt ends, which are necessary for adapter ligation. This process also includes the addition of a phosphate group to the 5' end and an 'A' base to the 3' end to facilitate the ligation of adapters.3. **Adapter Ligation**: Short DNA sequences called adapters are ligated to the ends of the repaired DNA fragments. These adapters contain priming sites for PCR amplification and unique identifiers (indices) for multiplexing multiple samples in a single sequencing run.4. **Amplification**: The adapter-modified DNA is amplified using PCR to increase the quantity of the library to detectable levels for sequencing.5. **Quality Control**: The final library is assessed for concentration, size distribution, and adapter dimer contamination before it is ready for sequencing.NGS library preparation methods have evolved over time, with various kits and protocols optimized for different sequencing platforms and applications. Commonly used library preparation kits provide streamlined processes that may include all reagents and instructions needed to prepare libraries efficiently.