In the last two decades, the development of massive parallel sequencing
methods has allowed the sequencing of RNA at an unprecedented resolution,
unleashing an enormous wealth of information about the cellular state. Sequencing has
accelerated biomedical research by identifying novel mutations, aberrant splicing
patterns, splicing isoforms, new gene regulators, and cell-to-cell heterogeneity. In order
to efficiently characterize the complexity of the complete transcriptome, there is a
steady development for different RNA sequencing [RNA-seq] protocols by improving
different steps from library preparation to the data analysis. Furthermore, with the
advancements in the sequencing strategies, single-cell RNA sequencing[scRNA-seq]
methods have been developed allowing to address the heterogeneity in cell types, and
mRNA expression at a remarkable resolution. The majority of these methods involve
the conversion of RNA to cDNA and thus amenable to errors, PCR and ligation biases,
and inefficiencies of enzymes. Amid these challenges, strategies have been developed
to sequence the RNA directly at the single-molecule level which allows to overcome
these biases. This chapter provides a brief overview of different sequencing
technologies available for the RNA-seq, scRNA-seq and single molecule RNA
sequencing along with the different aspects where RNA sequencing has contributed to
the biomedical field.
Keywords: Direct RNA sequencing, Different sequencing strategies, Next
generation sequencing, RNA-seq, RNA-related diseases, ScRNA-seq.
