Restriction Analysis Challenge

Restriction analysis is especially important in checking the structures of recombinant DNA molecules and in analyzing an unknown DNA. This chapter shows some examples with some typical restriction analysis problems encountered by scientists in the laboratory. Observing the sizes of fragments produced, scientists determine restriction site locations that would give them the patterns they see. A linear (not circular) piece of DNA is digested with the restriction endonuclease EcoRI and gives fragments of the following sizes: 3,000, 3,600, and 3,400 bp. When digested with BamHI, the DNA molecule gives fragments of the following sizes: 4,500, 3,000, and 2,500 bp. A double digest with EcoRI and BamHI gives fragments of the following sizes: 2,500, 500, 3,600, 3,000, and 400 bp. The distances between the restriction sites in base pairs are indicated, and the sites EcoRI or BamHI are appropriately labeled.