Download Investigation into Human Height

Investigation into Human Height
Question: Is human height the result of simple or polygenic inheritance?
Name:
Per:
Date:
Background:
So far, we have mostly studied traits that follow simple rules of genetics. These traits are encoded for by a
single set of genes with two possible alleles, dominant and recessive. A person either shows the dominant
phenotype or the recessive phenotype, but nothing in between them. A trait can be more complex when
there is a middle phenotype expressed by the heterozygote (LL = large, Ll =medium, ll = small). This is
called incomplete dominance and it produces three different phenotypes. Some traits are complex because
multiple genes encode them. These are referred to as polygenic traits and these traits show a range of
phenotypes. Traits encoded for by numerous genes show a normal distribution (bell-shaped curve). See
figure 1
Figure 1. Distribution of a trait depends on the number of genes for a trait.
Hypothesis: Write your own hypothesis below based on the question and background knowledge.
Procedure:
1. Measure your height in cm. If you already know your height, you can convert to cm (1 inch = 2.54 cm)
Your height in cm: __________
2. Compile data from the entire class(es) and fill out the data table below.
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Data:
Height Range (cm)
141-145
146-150
151-155
156-160
161-165
166-170
171-175
176-180
181-185
186-190
191-195
Number of Students
Transform the data: Construct a histogram of the class data. Give your histogram a title and make sure that
all of the axes and data are properly labeled
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Analysis and Interpretation: Answer each in complete sentences.
1. Was your hypothesis supported by the data? Is human height the product of simple inheritance or
complex polygenic inheritance?
2. How does your data support this interpretation? What do the data mean?
3. How would you change or improve this investigation?
4. What other traits, if investigated, do you think would be the product of polygenic inheritance? Why?
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