Download 5. To determine the genotype of your offspring for the traits

CLASS SET! Don’t Write on!
Problem: How are traits passed on from generation to generation to create variations in each individual’s
facial features?
Background:
Gregor Mendel determined that hereditary traits, or genes, are passed on from generation to generation
with predictable outcomes. In this stimulation, you will illustrate the genetic concepts of dominance,
segregation, independent assortment, genotype, phenotype, dominant-recessive inheritance, incomplete
dominance, and polygenic inheritance when you are your lab partner “produce” a baby.
Most of the traits in this activity were created to illustrate how human heredity works in a simplified model
and to reinforce basic genetic principles. In reality, inherited characteristics of the face are much more
complicated than this activity illustrates. Most of these facial characteristics are determined by many genes
working together in ways we do not yet understand.
Objectives:
After completing this investigation you will be able to:
1. Recognize the relationship between an individual’s genotype and phenotype.
2. Describe the role of probability in inheritance.
3. Differentiate between dominant-recessive, incomplete dominant, and polygenic traits.
4. Differentiate between homozygous and heterozygous genotypes.
Materials:
Two coins; two dice, colored pencils, markers, or crayons; white paper.
Procedure:
1. Define genotype and phenotype of the top of the page with your data table.
2. Choose the traits of the parents and give them names. These can be your names and traits, or fictitious
names and traits combinations that you generate… have fun! ☺
3. Determine the gender of your offspring. Only the father should roll the die because the father
determines the sex of the offspring. If the father donates a Y chromosome the baby will be a boy. If the
father donates an X chromosome, the baby will be a girl. The mother can only give an X.
4. Name your offspring!
5. To determine the genotype of your offspring for the traits listed in your data table, create punnett squares
with your partner by combining your genotypes to determine the possible outcomes. Roll dice to determine
which genotype they receive. If you roll a 1, select the top left square, 2=top right square, 3=bottom right,
4=bottom left. 5 or 6=roll again. **Please see student page for special rules for Polygenic Traits:
7. After rolling the die, record the genotype and phenotype of the offspring in your data table.
8. When you have determined all of your offspring’s facial features, draw and color the way the offspring
will look as a teenager. Make sure your offspring’s head and features are drawn using an accurate scale.