The NCBE has developed a range of materials and practical protocols to help with education about DNA and modern genetics.
Gel electrophoresis is a key technique in modern biology. It is used to separate DNA fragments of different sizes. First, a gel is cast from agarose — a very pure form of agar, which is obtained from seaweed. At one end of the slab of gel are several small wells, made by the teeth of a comb that was placed in the gel before it set. A buffer solution is poured over the gel, so that it fills the wells and makes contact with the electrodes at each end of the gel. Ions in the buffer solution conduct electricity. The DNA fragments are mixed with a small volume of loading dye. This dye is dissolved in a dense sugar solution, so that when it is added to the wells, it sinks to the bottom, taking the DNA with it.
An electrical potential is applied across the gel. Phosphate groups give the DNA fragments a negative electrical charge, so that the DNA migrates through the gel towards the positive electrode. Small fragments move quickly through the porous gel — larger fragments travel more slowly. In this way the pieces of DNA are separated by size. The loading dye also moves through the gel, so that the progress of the electrophoresis can be seen.
After electrophoresis, the gel is stained with a harmless dye to reveal the DNA.
UNIQUE, AWARD-WINNING, SAFE, TECHNOLOGY
The enzymes and DNA in the NCBE’s award-winning kits are dried. These reagents can be transported and stored at room temperature instead of the -20 °C that is normally required for such delicate biological molecules.
To dispense small volumes of reagents with the required precision, the NCBE has coupled special microsyringes with calibrated tips, providing a low-cost yet highly accurate alternative to conventional micropipettes.
The kits include the NCBE’s patented gel electrophoresis apparatus incorporating carbon fibre electrodes rather than the platinum that is normally used.
The equipment is powered by low-voltage batteries or an inexpensive, safe and effective 36 volt mains transformer.
To stain the DNA on the gel the kits use Azure A in preference to highly mutagenic ethidium bromide and ultraviolet light or — the usual alternative — methylene blue (which is relatively insensitive). Consequently, our equipment is safe for classroom use.
THE POLYMERASE CHAIN REACTION
The polymerase chain reaction (PCR) is one of the most important and powerful methods in molecular biology. It enables millions of copies of specific DNA sequences to be made easily and quickly. The technique and variations of it are used extensively in medicine, in molecular genetics and in pure research.
The Plant evolution module provides materials for the simple extraction of chloroplast DNA from plant tissue, its amplification by the PCR, and gel electrophoresis of the PCR product.
Students can use plants of their choice and identify possible evolutionary relationships between different species. This mirrors the molecular methods used in modern plant taxonomy.
This activity presents an ideal opportunity for open-ended investigations by individual students or groups.
NEW BACTERIAL TRANSFORMATION KIT
Genetic modification has featured in school science courses since the mid-1980s. Yet despite its importance, very little relevant practical work is done in UK schools and colleges to help students learn about this important topic, particularly in the 14-16 age range.
The NCBE's new bacterial transformation kit was developed to help meet this need. With the kit, students add plasmid DNA to cultures of bacteria. Those cells that take up the plasmid produce green fluorescent protein.
The kit includes ideas for open-ended practical investigations suitable for older students.
The kit features several innovative technologies that make the protocol quick, easy and reliable.