DNA sequencing
![An example of the results of automated chain-termination DNA sequencing.](/Images/godic/202412/23/Radioactive_Fluorescent_Seq3155.jpg")
![Genomic DNA is fragmented into random pieces and cloned as a bacterial library. DNA from individual bacterial clones is sequenced and the sequence is assembled by using overlapping DNA regions.(click to expand)](/Images/godic/202412/23/DNA_Sequencing_gDNA_libraries3155.jpg")
![Multiple, fragmented sequence reads must be assembled together on the basis of their overlapping areas.](/Images/godic/202412/23/Mapping_Reads3155.png")
![An Illumina HiSeq 2500 sequencer](/Images/godic/202412/23/Illumina_HiSeq_25003155.jpg")
DNA sequencing is the process of determining the precise order of nucleotides within a DNA molecule. It includes any method or technology that is used to determine the order of the four bases—adenine, guanine, cytosine, and thymine—in a strand of DNA. The advent of rapid DNA sequencing methods has greatly accelerated biological and medical research and discovery.