What is a dna ladder?

A DNA ladder is a mixture of DNA fragments of known length that are used as a reference marker in gel electrophoresis. It consists of standard DNA fragments with specific base pair lengths, typically ranging from 100 to 10,000 base pairs. By running a DNA ladder alongside samples of unknown DNA, scientists can determine the size of the fragments in the sample by comparing their migration distances on the gel to the standard ladder. DNA ladders are commonly used in molecular biology research, forensic analysis, and genetic testing.