Our laboratory offers the latest techniques in molecular biology, including NGS.

The sequencing of DNA/RNA molecules.

The advent of genetics and the study of DNA has been accompanied by an accelerated evolution in genomic techniques. First generation (or Sanger) sequencing of DNA introduced in 1980 was the first step and made possible the human genome sequencing project, which started in 1998 and lasted nearly 15 years with a cost of 3 billion dollars.

This project much revived sequencing techniques and within 10 years, high throughput sequencing or new generation sequencing (NGS) had arrived in laboratories. The NGS techniques permitted an acceleration of genome sequencing and drastic reductions in costs.

The arrival of sequencing techniques coincided with the emergence of bioinformatics providing the needed tools to analyze the data generated by the sequencers.

NGS: New generation sequencing (2^nd generation)

Compared to Sanger sequencing, NGS is more powerful allowing sequencing on a much larger scale with the capacity to simultaneously generate huge datasets on several thousand or even millions of DNA molecules in a single run.

The read length of this short-read sequencing approach never exceeds 300 nucleotides. The most frequently used technology is sequencing by synthesis (Illumina sequencing).

While short-read sequencing remains a very powerful technique, it requires the analysis of small fragments as they are incorporated end to end during the assembly of genes or whole genomes.

This can become highly complicated when the task involves covering complex genomic sequences (genome) of very large size (greater than the fragments read by NGS) comprising insertions, deletions, duplications and other rearrangements.

Long-read sequencing (3rd generation)

Currently, there exists two main long-read sequencers, known as 3rd generation: Pacific Biosciences (PacBio) and Oxford Nanopore Technologies (ONT). Both allow the sequencing of much longer fragments (up to 100 kilobases).

The ONT sequencer revolutionized high throughput sequencing by offering a real-time sequencing of DNA strands as they pass through nanopores which measure the electrical signal emitted by each nucleotide. This technology offers the advantages of requiring neither polymerase activity nor sequencing by synthesis of complementary strands.

Application of the ONT long-read sequencing

Our team are skilled in the techniques involved in nanopore sequencing for specific applications.

Case study in our laboratory

Long-read ONT sequencing to monitor fungicide resistance. 

A NGS analysis first requires the preparation of a library or bank composed of the group of fragments of interest..