DNA sequencing DNA sequencing

DNA sequencing

A DNA molecule is a polymer consisting of two long chains bound together and coiled in a helix. The chains are made of repeating segments, called nucleotides or bases, and labelled A, T, C, and G. The connections between the two chains are made through hydrogen bonds between complementary base pairs, A with T and C with G. A particular arrangement of the nucleotides contains genetic instructions for the growth, functioning, and reproduction of all living organisms. The variations of the code account for all diversity of life forms on Earth and endless distinctions of the members of a given species. No two humans are exactly the same, a fact known in forensic science where evidence based on the DNA is one of the strongest against a perpetrator. Ordering of nucleotides in the DNA – the DNA code – has become an essential analytical and diagnostic tool in numerous areas of biology, medicine, evolution, forensics, virology, and more. DNA sequencing refers to any technique of determining the sequence of nucleotides in DNA. For example, dye-terminator sequencing is one that uses light.

DNA sequence

The first generation of DNA sequencing was the Sanger method, named after two-time Nobel Laureate Frederick Sanger. This was the method used to decipher the human genome in 2003. This process was gel-electrophoresis based and took over a decade to produce the first human genome sequence. In automated Sanger sequencing, a computer reads each band of the capillary gel, in order, using fluorescence to call the identity of each terminal nucleotide. More recently, higher throughput methods, known as next-gen sequencing (NGS) techniques, have replaced the majority of electrophoresis-based Sanger methods.

 

Most of these NGS techniques still employ light to determine the sequence of nucleotides.  For example, in some variants of the dye-terminator model, fluorescently labeled nucleotides are cyclically added to build complementary strands from target DNA fragments immobilized on a surface.  The process of building the new strand is called DNA polymerization, and the label serves as a reversible terminator so that only one nucleotide is added to the growing nucleic acid chain in each cycle. In the sequencing instrument, the fragments are illuminated by light from lasers, and the resulting fluorescence emission, at specific wavelengths that identify the terminating nucleotide, is detected by high-sensitivity cameras or other photodetectors. After the identification of the base pair, the terminator is cleaved, removing the fluorescence signal for that nucleotide and allowing the next terminating base to continue the polymerization in the subsequent cycle. Other popular optical DNA sequencing technologies include techniques that limit the volume of light detected to only the size of single nucleotides through tiny wells or pores.

 

For DNA sequencers, we offer a lineup of high-sensitivity image sensors and cameras that are optimal for detecting extremely weak light.

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These CMOS cameras feature high sensitivity and low noise levels, making them optimal for observing extremely weak light. We can also customize the product to best suit your needs.

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The C10000-801 is a camera enabling you to capture a wide range of images at higher speed and higher sensitivity. This is achieved by synchronizing the object motion with CCD charge transfer. This camera is used for applications requiring high-speed detection of extremely weak light, such as analyzers and imaging devices.

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