DNA and Genetic Engineering: Practical Protocols for School Science, Including an Original Human Cheek Cell DNA Extraction Method

This article, published in the New Zealand Science Teachers Journal (Vol. 103, 2003), presents practical open-source protocols for DNA extraction and gel electrophoresis designed for primary and secondary school students, developed through the Nexus Research Group (NRG) at Inglewood High School, New Zealand. The article is notable for including an original human cheek cell DNA extraction protocol independently developed by the authors at the NRG, explicitly credited as such in the text with a request for attribution. The human DNA extraction protocol uses household materials ( salt, water, dish-washing detergent, and cold ethanol ) to isolate cheek cell DNA visible as spooled strands at a liquid interface. Chemical confirmation tests for purines, phosphate, and deoxyribose are provided. A plant DNA extraction protocol using cauliflower is also described. Both protocols exemplify the Nexus Research Group's founding principle of making authentic scientific investigation accessible without requiring costly or specialised equipment. The article also presents a complete DIY gel electrophoresis protocol constructed from a soap dish, 9-volt batteries, aluminium foil electrodes, agar gel, and glycerol. Faster results are achieved using food colouring to simulate DNA fragment separation at school level using entirely low-cost materials. Safety guidance is provided throughout, including an explicit warning against the use of carcinogenic ethidium bromide. The conceptual sections explain DNA structure, the genetic code, codon-based protein synthesis, genetic engineering, and viral reproduction at a level accessible to secondary school students. The practical protocols follow a three-stage approach; construct the apparatus, verify correct operation, conduct authentic investigation. The author would later formalise these stages as the Build It - Test It - Use It pedagogical framework. This article represents an early published instance of that framework applied to molecular biology at school level. The NRG human cheek cell DNA extraction protocol has been identified in subsequent teaching resources without attribution. This Zenodo record establishes permanent open-access documentation of the protocol's origin and date of publication. Users of the protocol are requested to acknowledge: Fenton, M., & Fenton, C. (2003). DNA and genetic engineering. New Zealand Science Teachers Journal, 103. [This record's DOI] Reproduced under the NZASE journal copyright notice, which permits educational and scientific organisations to reproduce material without prior notification. The content came from the original article on the Nexus Research Group website,