DNA and RNA Sequencing

The ability to detect the sequence of nucleobases in DNA or RNA is vital for understanding their function. This chapter outlines both the history of DNA and RNA sequencing and the current leading technologies. These have generated the ability to sequence billions of nucleotides simultaneously and single molecules of millions of bases in length. As of 2020, determining the sequence of a human genome takes 1 day and costs approximately $1000. Uses of sequencing beyond the detection of the underlying gene codes include mapping protein–DNA interactions, profiling gene expression and tracking modified bases. First, second and third generation technological breakthroughs have brought about a revolution in sequencing capabilities, which have had effects on scientific research and clinical medicine. Alternative technologies also have their place, including DNA fingerprinting, DNA microarrays and locating nucleic acid sequences within living cells. Interrogation of gene sequence inside a single cell is in its infancy of showing results.