The New World of Isoform Sequencing

from Genetic Engineering News by Jonas Korlach

Long-Read Sequencing Can Offer the Most Comprehensive View Yet of Gene Activity


Bcl-x is a classic example of how two gene isoforms can have opposite biological effects, depending on whether a particular exon is retained or spliced out.

Not too long ago, the life sciences community was still debating whether sequencers would ever overtake microarrays as the preferred means of measuring gene expression. Today, not only have sequencers become the standard workhorse for gene expression studies, but newer sequencing technology has delivered the ability to generate novel expression data even in the most well-characterized cells or organisms. Truly, it is a remarkable time for comprehensive studies of which genes are being transcribed, with the goal of providing functional insight into various biological processes.The key advantage sequencing holds over microarrays is its ability to deeply survey an entire transcriptome, while microarrays are limited to interrogating known genes using probes designed from a reference genome assembly. As next-generation sequencing became more affordable, scientists were eager to switch to this approach, which became known as RNA sequencing or simply RNA-seq.

Recently, scientists have begun applying long-read sequencing to further advance the field of gene expression, finding that this method can directly sequence full-length transcripts and provide additional insights into gene isoforms. In doing so, this technique has generated a more comprehensive view of full-length, protein-coding gene transcription than other sequencing technologies for the clearest view yet of a transcriptome.

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