Fragmenttianalyysiä

Fragmenttianalyysiä, known in English as fragment analysis, is a technique used in molecular biology and genetics to determine the size of DNA fragments. It is a crucial method for various applications, including genetic testing, forensic science, and disease diagnosis. The process typically involves separating DNA fragments based on their size using capillary electrophoresis.

The DNA sample is first amplified using PCR to generate specific fragments of interest. These fragments are then labeled with fluorescent dyes. The labeled fragments are loaded into a capillary filled with a polymer matrix and subjected to an electric current. Smaller fragments migrate faster through the matrix than larger fragments. A laser excites the fluorescent dyes, and a detector records the emitted light, generating a signal that is proportional to the size and quantity of the DNA fragments.

The output of fragment analysis is a electropherogram, which is a graph showing the fluorescent signal intensity over time. Each peak on the electropherogram corresponds to a DNA fragment of a specific size. The position and height of the peaks are used to identify and quantify the fragments. This allows for precise determination of fragment lengths, often with a resolution of a single base pair.

Fragment analysis is widely used for applications such as STR (short tandem repeat) analysis in DNA profiling, determining the length of PCR products for genotyping, and detecting mutations or variations in DNA sequences. Its accuracy and sensitivity make it an indispensable tool in modern molecular diagnostics and research.