Genetics and DNA Demonstrations

See also: Genetics and DNA

Genetics is the study of inheritance and variation, while DNA is the molecule that carries genetic information. This category looks at how traits are passed from one generation to the next, the structure and function of DNA, and the role of genes in development and health. Studying genetics and DNA helps explain both continuity and diversity in living things.

Demonstration	Materials	Difficulty	Safety	Summary
Genetic Inheritance in Brassica rapa	★★★	★★☆	★☆☆	Students investigate Mendelian inheritance in Brassica rapa by studying two traits: stem height (tall vs. dwarf) and stem color (purple vs. green). They grow F1 and F2 generations, predict outcomes with Punnett squares, then compare predictions with actual phenotypic ratios using class data.
PTC Genetic Taste Test	★★★	★☆☆	★☆☆	The ability to taste phenylthiocarbamide (PTC) is controlled by a single gene, TAS2R38, which codes for a bitter taste receptor. Variants of this gene determine whether individuals find PTC intensely bitter, slightly bitter, or tasteless. This simple Mendelian trait illustrates genetic variation, natural selection, and sensory perception.
Simulated Blood Typing	★★★	★☆☆	★☆☆	Students use a simulated blood typing kit to identify the ABO and Rh blood groups of synthetic blood samples. The activity demonstrates how agglutination reactions work in real blood typing while remaining completely safe.
DNA Extraction From Kiwi Fruit	★★☆	★★☆	★☆☆	This experiment demonstrates how DNA can be extracted from fruit cells, such as from kiwi fruit. The DNA becomes visible as strands at the boundary between the fruit extract and chilled ethanol.
Mitosis in Onion Root Cells	★★☆	★☆☆	★☆☆	Students use digitized images of onion root tips to identify different stages of the cell cycle. By counting the number of cells in each stage, they estimate how much time cells spend in interphase, prophase, metaphase, anaphase, and telophase.
Onion Root Tip Mitosis	★★☆	★★☆	★☆☆	This experiment demonstrates mitosis by preparing and observing stained onion root tip cells under a compound microscope. Students identify the stages of mitosis while understanding why onion root tips are suitable for studying active cell division.
Strawberry DNA Extraction	★★☆	★★☆	★★☆	By crushing strawberries and treating them with detergent, salt, and alcohol, students can extract visible strands of DNA. The detergent breaks open the cells, salt keeps proteins separate, and alcohol causes DNA to clump so it can be seen with the naked eye.
Coin Toss Genetics	★☆☆	★☆☆	★☆☆	Students use coin tosses to simulate allele segregation during meiosis and fertilization. By representing dominant and recessive alleles with coin sides, they explore probability, monohybrid inheritance, and variation between predicted and observed genetic ratios.
DNA Paper Model	★☆☆	★☆☆	★☆☆	Students cut, arrange, and assemble paper templates of sugars, phosphates, and nitrogen bases to construct a model of DNA. The activity reinforces the structure of DNA, base pairing rules, and the appearance of the double helix.
Dominance and Recessiveness with Food Coloring	★☆☆	★★☆	★★☆	This demonstration uses colored water, bleach, and food coloring to model how dominant, recessive, and codominant traits are expressed. By mixing colors in different combinations, students see how phenotypes appear in offspring.
Genetic Traits Survey	★☆☆	★☆☆	★☆☆	Students survey their own observable traits such as earlobe attachment, tongue rolling, freckles, and handedness to explore patterns of inheritance. By collecting and analyzing class data, they investigate how genetic traits vary in populations and how environment can also influence expression.
Hardy Weinberg Bead Simulation	★☆☆	★★☆	★☆☆	Students model allele and genotype frequencies with colored beads under two scenarios: random mating and selection against a recessive homozygote.
Modeling DNA with Pipe Cleaners	★☆☆	★☆☆	★☆☆	Students use beads and pipe cleaners to model the structure of DNA. Colored beads represent the four bases (A, T, G, C), while pipe cleaners represent the sugar-phosphate backbone. The model demonstrates base-pairing rules and the twisted double-helix structure.
Origami DNA Model	★☆☆	★☆☆	★☆☆	This hands-on activity uses paper folding (origami) to create a model of the DNA double helix. By folding and coloring paper strips, students can explore how complementary base pairs (A with T, C with G) form the steps of the twisted ladder structure of DNA.

Materials
★☆☆ Easy to get from supermarket or hardware store
★★☆ Available in most school laboratories or specialist stores
★★★ Requires materials not commonly found in school laboratories

Difficulty
★☆☆ Can be easily done by most teenagers
★★☆ Available in most school laboratories or specialist stores
★★★ Requires a more experienced teacher

Safety
★☆☆ Minimal safety procedures required
★★☆ Some safety precautions required to perform safely
★★★ Only to be attempted with adequate safety procedures and trained staff