NGS Uncovered: Simple Animations to Understand Next-Gen Sequencing

DNA library preparation begins with genomic DNA, which consists of very long strands thousands of base pairs in length.The DNA is then fragmented into smaller pieces using mechanical or enzymatic methods. This creates fragments of various sizes.We select fragments between 150 and 300 base pairs in length. This size range is optimal for sequencing.Next, we attach special adapter sequences to both ends of each fragment. These adapters act like barcodes and will allow the fragments to bind to the sequencing flow cell.The flow cell surface contains complementary adapter sequences. The fragments can now bind to these sequences through their attached adapters.These binding sites are distributed across the flow cell surface, allowing millions of fragments to attach simultaneously.The bridge amplification process begins on the flow cell surface.DNA fragments with special adapter sequences attach to complementary sequences on the flow cell.The free end of the DNA fragment bends over and attaches to a nearby binding site, forming a bridge.DNA polymerase enzymes then create copies of the original DNA fragment.This process repeats multiple times, with each copy able to form new bridges.Each cluster grows exponentially, eventually containing thousands of identical DNA fragments.Across the entire flow cell surface, millions of these clusters form simultaneously, each containing identical copies of a unique DNA fragment.With our clusters formed, we're ready to begin the sequencing process.In sequencing by synthesis, we add fluorescently labeled nucleotides to our DNA clusters.Each nucleotide type has a unique fluorescent label. When incorporated, it emits a specific color signal.The computer processes millions of these signals simultaneously, converting them into readable DNA sequences.This process continues for millions of clusters across the flow cell, generating massive amounts of DNA sequence data.This technology allows us to sequence millions of DNA fragments simultaneously, revolutionizing our ability to read genetic information.Thanks for learning about DNA sequencing with Spark.E!