Use a dry erase marker to mark one coin with the letter "F"to designate the student's mother and the other coin with the letter "M" to designate the student's father.
List various physical traits on a piece of paper and list options next to each trait for male and female dominant and recessive genes. This form will be used to create a smiley face determined by the flip of a coin. List physical characteristics, such as face shape, nose size, hair style, freckles and hair length. Provide students with a key that outlines each physical trait with one example for recessive genes and one example for dominant ones. A round face in dominant traits and an oval-shaped face with recessive genes is an example for this key.
Instruct students to flip both coins for each physical trait listed on the paper. The coin that lands on heads will be the dominant trait. The recessive trait is the coin that lands on tails. For instance, when determining face shape, an "F" coin that lands on heads would beat out a "M" coin that lands on tails. In this case, the female coin would contribute the dominant gene dictating a round head for the smiley face. If both coins land on heads or tails, the trait associated with that side of the coin would be placed on the smiley face.
Instruct students to begin circling the resulting traits to build a smiley face. Students should double-check their results to ensure that the dominant trait is being selected.
Have students draw their smiley face using the key of dominant traits resulting from the coin flip. Explain that the students' own physical and physiological traits were determined in a similar, if not more-complicated, process within their own genome. Use supplemental videos and graphs to explain the placement of genes on the DNA helix, using the coin-flip to make the lesson come to life.