Final answer:
The sizes of DNA fragments in gel electrophoresis reflect the length of the fragments, where smaller fragments move faster and further, allowing scientists to estimate fragment sizes and analyze genetic differences.
Step-by-step explanation:
The size of restriction fragments as determined by migration speed in gel electrophoresis can teach us about the DNA fragment lengths present in a sample. As DNA fragments are negatively charged, they migrate towards the positive electrode in an agarose gel. The rate of migration is inversely proportional to the size of DNA fragments, meaning smaller fragments move faster and travel further. This principle can be used in techniques such as restriction fragment length polymorphism (RFLP) analysis, where DNA samples digested by restriction enzymes produce distinctive banding patterns.
By comparing the bands with a known marker or DNA ladder, researchers can estimate the sizes of the fragments present. These sizes may indicate the number of base pairs, the presence of specific genes, or genetic variations within the sample. Gel electrophoresis can thereby provide valuable insights into the genetic composition of an organism or the success of molecular biology procedures such as restriction enzyme digestion.