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Evolution and Medicine – a New
Approach for High School Biology
May 10, 2011
Evolution and Medicine – a New
Approach for High School Biology
Paul Beardsley
May 10, 2011
Section I
Introduction
Biological Sciences Curriculum Study
• Established in 1958
• Nonprofit organization
• Three main areas of emphasis
– Curriculum Development
– Professional Development
– Research and Evaluation
NIH Curriculum Supplement Series
Free curriculum supplements
http://science.education.nih.gov
NIH – Evolution and Medicine
• Sponsored by:
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National Institute of General Medical Sciences
National Institute of Neurological Disorders and Stroke
National Eye Institute
National Heart, Lung, and Blood Institute
National Institute of Allergy and Infectious Diseases
National Institute on Drug Abuse
National Institute of Dental and Craniofacial Research
National Institute on Aging
National Cancer Institute
National Center for Research Resources
Office of the Director
• What features would you like to
see in a short curriculum that
focuses on evolution?
Evolution is Relevant— Hillis 2007
• Ten Ways to Improve Evolution
Coverage in Biology Textbooks…
1. Demonstrate that evolutionary
research is current and ongoing
3. Use fresh examples.
4. Show how evolution is relevant
to human lives.
Let’s pause for questions
from the audience
Section 2
Overview of Evolution and
Medicine
Engage: Ideas about the role of
evolution in medicine
• Students provide initial explanations for
the evolution of MRSA.
• Students examine data from Pax6,
consider how common ancestry explains
the value of model organisms.
Adapted from: Washington NL, Haendel MA, Mungall CJ, Ashburner M, Westerfield M, et al. 2009. Linking Human
Diseases to Animal Models Using Ontology-Based Phenotype Annotation. PLoS Biology 7(11): e1000247.
doi:10.1371/journal.pbio.1000247
Explore: Investigating
Lactose Intolerance and Evolution
• Students investigate lactase
persistence in humans
– Perform a lab experiment
– Provide initial explanations for patterns
– Study the genetic basis for lactase
persistence
– Compare alternative
hypotheses
Explain: Evolutionary processes and
patterns inform medicine
• Students solve a
medical mystery
involving alphathalassemia
• Apply natural
selection to explain
the disease’s high
incidence.
Explain: Evolutionary processes and
patterns inform medicine
• Students compare
sequences across
species for gene
associated with cleft
palette.
• Students explain the
results in terms of
common ancestry
• Explain how natural
selection conserved
certain sequences
Elaborate: Using evolution to
understand influenza
 Align sequences of
the hemagglutinin
gene
 Learn about the
hemagglutinin region
and the immune
system
 Relate principles of
natural selection to
the need for new
vaccines
Evaluate: Evaluating
evolutionary explanations
• Students evaluate an article
about the evolution of vitamin
C synthesis written for a
school publication
• Compare each example of
natural selection encountered
in the supplement.
Let’s pause for questions
from the audience
Section 3
Lesson 1— Anaridia: An Eye
Disease
• Students learn about the rare
disease aniridia, caused by
mutations in Pax6.
• Students investigate data on Pax6
and contribute their ideas.
What can you infer about the Pax6
gene from the protein sequences
from these four species?
Adapted from: Washington NL, Haendel MA, Mungall CJ, Ashburner M, Westerfield M, et al. 2009. Linking Human Diseases to Animal
Models Using Ontology-Based Phenotype Annotation. PLoS Biology 7(11): e1000247. doi:10.1371/journal.pbio.1000247
On the basis of the pictures, do you think the
function of the Pax6 gene is similar in all four
species? Explain your reasoning.
Transition to model species…
• Does the evolutionary
tree suggest that the
mouse is more closely
related to the zebrafish
or the fruit fly?
• How would students
answer?
– A. Zebrafish
– B. Fruitfly
– C. Don’t know
Do you think that the common
ancestor of fruit flies, zebrafish,
mice, and humans had a gene
similar to Pax6?
How does shared ancestry
explain why scientists can use
model organisms to learn about
human health?
Let’s pause for questions
from the audience
Section 4
Lactose Intolerance and Evolution
Explore: Investigating
Lactose Intolerance and Evolution
• Students hear about an Asian
teenager who moved to the US and
began to suffer digestive problems
after consuming milk.
• Investigate simulated lactase samples
from patients around the world
Lesson 2: Lactose Intolerance and Evolution
Working site
Lesson 2: Lactase Intolerance and Evolution
Working site
Lesson 2: Lactase Intolerance and Evolution
Working site
Gender
Age
What type of mutation causes the difference
between lactase persistence and lactase
nonpersistence?
A mutation to the coding region
for the lactase enzyme
A mutation to a regulatory region
for the production of lactase
Scientists have identified specific mutations
that cause lactase persistence…
Thinking about genetics
What does it mean for the evolution
of lactase persistence if all people
who are lactase persistent don’t
have Mutation 1?
Explaining the Evolution of
Lactase Persistence
1.Culture-historical hypothesis:
In populations that herd and milk
cows, goats, or camels, lactase
persistence provides a selective
advantage due to a higher level
of nutrition or increased access
to water
Explaining the Evolution of Lactase
Persistence
2. Calcium hypothesis:
• Vitamin D helps the body absorb calcium.
We can make vitamin D when UV light
penetrates the skin.
• Lactose also helps the body absorb
calcium found in milk.
• In populations exposed to low levels of UV
light, lactase persistence provides a
selective advantage (higher level of
calcium)
Figure 1: The following image shows the average daily ultraviolet (UV) exposure across
Earth’s surface. Darker colors indicate greater UV exposure.
Image copyright George Chaplin. Adapted with permission. American Journal of Physical Anthropology,
107(2), 1998, pp. 221-224. Copyright 1998 Wiley-Liss, Inc.
Approximate Number of
Time period skeletons
examined
Possible
cases of
rickets
3000 BCE
6*
616
CE 400-1000 635
0
CE 800-1100 1055
6
CE 1200
1
364
* Some researchers interpret these
skeletons differently and claim that they
do not show evidence of rickets.
Let’s pause for questions
from the audience
Section 5
Using Evolution to Guide Research
• Students learn about cleft lip and
palate
• Gene Irf6 is associated with one
form of cleft lip and palate
• Irf6 is active in mice as sides of
mouth fuse
• Goal: identify sections of the Irf6 gene that
have remained the same over large
amounts of time.
Species
Chimpanzee
Orangutan
Rhesus
monkey
Dog
Horse
Cat
Cow
Rat
Mouse
Guinea pig
Armadillo
Opossum
Time since
common
ancestry with
humans
(millions of
years)
8
15
30
97
97
97
97
91
91
91
105
176
Nucleotides that Similarity with
are the same
human
(number)
sequence (%)
1,685
1,653
1,628
99
97
96
1,221
1,209
1,149
891
612
573
572
1,039
518
72
71
68
52
36
34
34
61
30
• How much time is
involved in the
comparison of all
four species?
• A – 30 million years
• B – 20 million years
• C – 10 Million years
• D – None of these
Questions about how to calculate
time for an evoprint?
• Imagine you had an evoprint with these four
species. How much time would be
represented in this evoprint?
• Advanced classes: 3rd position in codon
• How does evolution explain why
certain regions of the Irf6 gene
have not changed over large
amounts of time?
Let’s pause for questions
from the audience
Thank you!
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