DNAketju

DNAketju, also known as DNA ladder or DNA sequencing gel, is a technique used in molecular biology to separate and visualize DNA fragments based on their size. The term "DNAketju" is derived from the Finnish word "ketju," meaning chain, which refers to the ladder-like pattern formed by the separated DNA fragments when viewed under ultraviolet light.

The process begins with the extraction of DNA from a sample, followed by its fragmentation using restriction enzymes or other methods. The fragmented DNA is then mixed with a loading dye and loaded onto an agarose gel, which is an aqueous solution of agarose, a type of polysaccharide. An electric field is applied to the gel, causing the DNA fragments to migrate towards the positive electrode. Smaller fragments migrate faster and travel further, while larger fragments migrate slower and travel shorter distances.

After electrophoresis, the gel is stained with a fluorescent dye, such as ethidium bromide or SYBR Safe, which binds to the DNA and emits ultraviolet light when exposed to UV radiation. When viewed under a UV transilluminator, the DNA fragments appear as a ladder-like pattern, with each band representing a DNA fragment of a specific size.

DNAketju is widely used in various applications, including DNA fingerprinting, genetic mapping, and the analysis of genetic variations. It is a simple, cost-effective, and widely accessible technique that provides valuable information about the structure and function of DNA.