Plastic Egg Genetics

Grade level: 9 or 12

Subject: Science 9, Science 30, Biology 30

Topics: Basic Mendelian Genetics (monohybrid cross), Incomplete Dominance, and Codominance

Materials:

• 8 Sets of all colored eggs (for groups of 4)

• corresponding colors and amount in candy or plastic pieces of some type, like buttons, centimeter cubes, or any colored manipulative that will fit. If you use candy, you will have to restock each egg, if you use plastic, you can use it from class to class and year to year. I like using small cuts of pipe cleaners as they look similar to chromosomes.

• one basket for each group of four students to hold plastic eggs

•one worksheet copy for each student

Preparation:

Get some packages of plastic eggs (the kind that split into halves to fill with candy--they are usually available around Easter time) and some matching-colored gumballs, jellybeans, Skittles, etc. to fill them. Get enough so that every student gets one or, preferably, two eggs each. Use the genotype and phenotype to accompany the activity. For example, the letters represent the color of the “chromosomes”. Using the chart, fill the eggs according to the key:

Chart:

Monohybrid Cross

BB= blue (two blue pipe cleaners)

Bb=blue (one blue one orange pipe cleaner)

bb= orange (two orange pipe cleaners)

Codominant Cross

CPCP or PP=purple

CPCR or PR= pink and purple

CpCRor RR=pink

*using pink and purple is probably not the best idea but these were the only two colours that I had that I had enough of the same size. This can confuse students because “P” for purple and “p” for pink looks like P is dominant so I gave the pink an “R” for Rose colour.

Incomplete Dominance

BB=blue (two blue pipe cleaners)

Bb=green (one blue one yellow pipe cleaner)

bb=yellow (two yellow pipe cleaners)

(*it is best to use different colours for each type of cress so students do not get confused (I used Bb already as blue but due to lack of colours to show this demonstration I had to reuse this)

Optional modifications:

You might use white candy to represent albinos or smash some of the candies to represent the incidence of mutation or genetic disease. You can also put only one or three pipe cleaners in an egg to represent non-disjunction. Also may want to change language to “grab two eggs that are heterozygous for the trait” to increase vocabulary understanding.

To ensure students know the codes go through example and put codes on the board.

Name: ______Date: ______

Plastic Egg Genetics

Monohybrid Cross

Example

  1. Egg #1
  2. Phenotype: blue
  3. Genotype: Bb, (blue, orange)


Bb
(blue) / bb
(orange)
Bb
(blue) / bb
(orange)
  1. Egg #2
  2. Phenotype: orange
  3. Genotype: bb (orange, orange)

Cross #1Grab two blue eggs

  • Egg #1
  • Phenotype:
  • Genotype:
  • Egg #2
  • Phenotype:
  • Genotype:)

Cross #2 Grab two different blue eggs

  • Egg #1
  • Phenotype:
  • Genotype:
  • Egg #2
  • Phenotype:
  • Genotype:)

Cross #3Grab 2 orange eggs

  • Egg #1
  • Phenotype:
  • Genotype:
  • Egg #2
  • Phenotype:
  • Genotype:)

Cross #4Grab an orange and a blue egg

  • Egg #1
  • Phenotype:
  • Genotype:
  • Egg #2
  • Phenotype:
  • Genotype:)

Codominant Cross

Cross #1Grabtwo pink eggs

  • Egg #1
  • Phenotype:
  • Genotype:
  • Egg #2
  • Phenotype:
  • Genotype:)

Cross #2Grabtwo purple eggs

  • Egg #1
  • Phenotype:
  • Genotype:
  • Egg #2
  • Phenotype:
  • Genotype:)

Cross #3 Grab two half purple/pink eggs

  • Egg #1
  • Phenotype:
  • Genotype:
  • Egg #2
  • Phenotype:
  • Genotype:)

Cross #3 Grab one half purple/pink egg and either a pink or purple egg

  • Egg #1
  • Phenotype:
  • Genotype:
  • Egg #2
  • Phenotype:
  • Genotype:)

Incomplete Dominance Cross

Cross #1Grab two blue eggs

  • Egg #1
  • Phenotype:
  • Genotype:
  • Egg #2
  • Phenotype:
  • Genotype:)

Cross #2Grab two yellow eggs

  • Egg #1
  • Phenotype:
  • Genotype:
  • Egg #2
  • Phenotype:
  • Genotype:)

Cross #3 Grab two green eggs

  • Egg #1
  • Phenotype:
  • Genotype:
  • Egg #2
  • Phenotype:
  • Genotype:)

Cross #3 Graba green egg and either a yellow or blue egg

  • Egg #1
  • Phenotype:
  • Genotype:
  • Egg #2
  • Phenotype:
  • Genotype:)