*Metabarcoding and Digital PCR (dPCR): Application in the Study of Neglected Tropical Diseases DOI: http://dx.doi.org/10.5772/intechopen.106272*

developed the first automated method for sequencing DNA [22], which was capable of sequencing fragments from 5 to 75 base pairs (bp), and in 1986, Hood and Smith designed the first automatic sequencer that used laser beams that recognize fluorescent markers on DNA [23–25]. By 1985, the first automated sequencers using gels (Applied Biosystems PRISM® 373) or polymer-coated capillaries (ABI PRISM® 310) appeared [26]. Later, in 2004, new sequencing methods emerged, based on pyrosequencing and the so-called next generation sequencing (NGS) platforms. Currently, due to the fact that new sequencers have appeared on the market that are capable of applying other sequencing technologies in parallel, it is more appropriate to speak of High-Throughput Sequencing (HTS) or massive sequencing. There are some variants of this technology such as sequencing by ligation (*sequencing by oligonucleotide ligation and detection*), sequencing by synthesis and semiconduction, and sequencing by synthesis in clusters (sequence length up to 600 bp). A third generation of sequencers is those that use single molecule sequencing (*single molecule real-time* [SMRT]) that allows sequencing of much longer molecules, up to 30 kb [27–29]. There are other sequencing technologies in the development phase, those based on nanopores; which are based on the identification of the different bases of the DNA chain, thanks to an optical signal or by the variation that occurs in an electric current when the chain passes through a nanopore anchored to a membrane, in situ nucleic acid sequencing; which is a progression of single-cell RNA sequencing methods, is performed intracellularly within intact tissues, thus preserving the spatial context of gene expression within and between cell types and sequencing based on direct observation with microscopy that uses electron microscopy and allows the DNA sequence to be read directly by optical methods without the need for amplification (**Figure 1**) [30, 31] .
