Tag Archives: GS20

Do You Still Remember Which NGS Sequencer Was The First On The Market?

gs-20It was 2005, when Roche launched the first NGS sequencer called the Genome Sequencer 20 (GS 20). This device was able to achieve read length of approx. 100 bp, with a total data output of approx. 20 Mbp per run.
As a consequence, sequencing of a bacterial genome of 5 Mbp (e.g. E. coli) with 20-fold coverage required 5 individual runs on the GS 20. Sequencing costs were in the range of several tens of thousands Euros, bringing the cost compared to Sanger sequencing down 10-fold.

Looking back it’s also difficult to imagine for me, that the GS 20 software at that time could handle genomes of a max size of 50 Mbp only.

Since then, 5 major leaps in the Roche/454 sequencer’s development took place:

  • GS 20 to GS FLX
  • GS FLX to GS FLX with Titanium chemistry
  • Launch of the desktop sequencer GS Junior
  • GS FLX Titanium to FLX+
  • FLX + to FLX++ sequencing (new GS FLX software v2.8)

This all happened in only 7 years.

The current Roche/454 FLX++ chemistry enables read length up to 1100 bp and read outputs of up to 1.2 Gbp per run. As a consequence, today, 8 years later, sequencing of a 5 Mbp bacterial strain can be done on a ¼ plate of a full run. The 9-10-fold longer reads make a great difference in respect to contig length and contig number of the genome assembly.

Meanwhile other NGS sequencers dominate the market. Nevertheless the Roche /454 technology is still of superior quality for de-novo sequencing of genomes of any size and for amplicon sequencing.