Can you discover the conditions that will make double stranded DNA denature and re-anneal?
The sentence “This structure has novel features which are of considerable biological interest” may be one of science’s most famous understatements. It was published in April 1953 in the Nature article where James Watson and Francis Crick revealed the structure of DNA, the molecule that carries genetic information. Watson and Crick (and Maurice Wilkins) shared a Nobel Prize for determining that DNA is a double stranded helix, held together by specific base pairing. They also predicted, correctly, that at times the base pairs separate allowing DNA to perform functions that are essential for life. In this lab, students will use a fluorescent dye to investigate the conditions that influence DNA structure and its transition from double helix to single strand, and vice versa.
Students can test conditions that influence Watson-Crick base pairing between complementary DNA strands, using temperature to differentiate between DNA of different sequences, and establishing the melting temperature of each sample. They will carry out three investigations exploring DNA composition, concentration, the chemical milieu and their influence on Watson-Crick pairing.
- Techniques utilized: Micropipetting.
- Time required: can be completed in one 45 min. class period, or extended into two 45-min periods or a single block.
- Reagents needed: ‘DNA Glow Lab’ reagents kit (included in this product).
Suggested skill level: Familiarity with DNA structure and Watson-Crick base pairing, from middle school to college.
The DNA Glow Lab kit contains reagents for 8 lab groups of up to 4 students each (32 students):
- DNA samples for analysis
- DNA binding dyes
- Glow Lab Dilution Buffer
- This activity is compatible with blueGel™, blueBox, or other blue light transilluminator systems
Required equipment (one per lab group):
- miniPCR™ thermal cycler (ideal set up) or water bath and floaties (workable).
- Blue light transilluminator (such as blueBox™ or blueGel™)
- These reagents require refrigerated storage.
- Shelf-life: 6 months when stored at 4 degrees.
Free miniPCR Learning Lab™ downloads: