Product name:DNA Marker Ⅱ
Description:
A DNA ladder usually contains a set of known DNA fragments with different sizes in base pairs (bp) or kilo bases (kb). These DNA fragments are separated and visualized as DNA bands on a gel. These separated DNA bands together look like a ladder on the gel (see pictures below) and therefore it is called DNA ladder. DNA ladders are used in gel electrophoresis to determine the size and quantity of testing DNA fragments of genomic, plasmid, and PCR DNA. Most DNA ladders are in liquid form. A few microliters of a DNA ladder is usually loaded on a gel with testing DNA fragments. The quantity of each DNA band is known once the loading volume is determined. After electrophoresis, the size and quantity of the testing DNA fragments may be determined by comparing with the size and quantity of the DNA bands in the DNA ladder. DNA ladders, DNA markers, nucleic acid ladders, and nucleic acid markers are interchangeable phrases. Some scientists may call them DNA standards or nucleic acid standards. The number before a DNA ladder indicates the size interval of the DNA fragments. For example, the sizes of the DNA fragments in a 100 bp DNA ladder are mostly separated by 100 bp and 1 kb DNA ladder contains most DNA fragments with 1 kb size difference. Some 100 bp DNA ladders have over 1 kb DNA fragments and some 1 kb ladders have many 100 bp DNA fragments.