Dear Dr. Fetta Mehouel

I feel Next-generation sequencing (NGS) is currently most popular. The global next-generation sequencing market size was valued at USD 8.30 billion in 2023. The market is projected to grow from USD 9.29 billion in 2024 to USD 27.55 billion by 2032. Please refer to the article attached below.

https://www.fortunebusinessinsights.com/industry-reports/next-generation-sequencing-ngs-market-101000

It all started with the first-generation technology represented by Sanger sequencing, which was largely superseded by newer, higher-throughput sequencing technologies. The second generation introduced massively parallel sequencing with platforms such as Illumina and Ion Torrent, enabling high-throughput sequencing. Among the second-generation sequencing platforms,

1) Roche’s 454 sequencing method, which relies on pyrosequencing, where the sequence is determined by detecting the release of pyrophosphate when nucleotides are added to the DNA template, and

2) Illumina sequencing platform which utilizes a sequencing-by-synthesis method based on reversible dye terminators.

have emerged as the widely used second-generation sequencing platforms.

Third-generation sequencing technologies represent the latest advancements in DNA sequencing, offering new approaches that overcome the limitations of previous generations.

1) PacBio Sequencing, which uses a single-molecule, real-time (SMRT) approach with fluorescently labeled nucleotides, enabling long-read sequencing of DNA fragments up to tens of kilobases in length and

2) Oxford Nanopore sequencing, based on nanopore technology, where a single-stranded DNA molecule passes through a nanopore, and changes in electrical current are measured to determine the DNA sequence.

You could use Sanger sequencing when interrogating a small region of DNA on a limited number of samples or genomic targets. But NGS will allow you to screen more samples cost-effectively and detect multiple variants across targeted areas of the genome, which otherwise would be costly and time-consuming using Sanger sequencing.

Regards,

Malcolm Nobre

Dear Dr. Malcolm Nobre Thanks so much fo all this information and details aboutsequencing techniques.

Houw about the technique of the Maxam-Gilbert? is it currentlly used ?

Kind regards,

Fetta Mehouel

Dear Dr. Fetta Mehouel

The Maxam–Gilbert sequencing method was widely used in the early days of DNA sequencing. This method has now been forgotten. So I didn't mention it earlier. During those days when both Maxam–Gilbert and Sanger sequencing were discovered, Maxam–Gilbert was more popular but not at present. This is because it is slow, is low-throughput, and uses dangerous chemicals. Sanger sequencing is still widespread.

Regards,

Malcolm

Dear Dr. Malcolm Nobre Thanks a lot for these explanations,I get it now.

Best regards

Fetta Mehouel

I would say Illumina is the most widely used platform due to its high accuracy, scalability, and ability to generate large volumes of data. It uses sequencing-by-synthesis (SBS) technology. I am not sure about the cost, maybe Oxford is the shipped one.

Dear Doctor Loubna Youssar Thanks so much for your reply.

Greetings

Thans so much dear Dr. Shler Ali Khorsheed

Kind regards

Fetta Mehouel

If you are talking about whole genome sequencing, undoubtedly the next generation sequencing, especially the Illumina and Ion Torrent platforms, however, for a smaller fragment sequencing or gene sequencing the Sanger sequencing method is the gold standard, popular and widely used method.

"For a smaller fragment sequencing or gene sequencing the Sanger sequencing method is the gold standard, popular and widely used method". You mean the first generation?