Bio 9B: Monday, 4.25.11 Title: Connecting Genetics and Evolution: Cystic Fibrosis Case Study
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Transcript of Bio 9B: Monday, 4.25.11 Title: Connecting Genetics and Evolution: Cystic Fibrosis Case Study
Bio 9B: Monday, 4.25.11Title: Connecting Genetics and Evolution: Cystic Fibrosis Case Study
Homework: Complete through analysis Question 1 for CF
Case Study (different than assignment sheet)
Do Now: What comes to mind when you hear the word
“EVOLUTION”
Today’s Objectives: Determine an organism’s genotype and phenotype by
analyzing their DNA sequences
INTRODUCTION TO EVOLUTIONPHA Biology 9
Moretti/ Dickson
EVOLUTION Genetic changes in a
species or population over time
Connecting Genetics and Evolution:Cystic Fibrosis Case Study
Purpose: Discuss mutations and their possible effects Learn about the effects of mutations that cause cystic
fibrosis Analyze DNA sequences to determine if and what kind of
mutations exist Whole Class Work:
Read the Background Information and Supporting Information
Paired Work: Complete the Pre-Activity Questions Determine the genotypes and phenotypes of 4 people for
the CFTR protein to identify whether or not they have Cystic Fibrosis
Individual Work: Read the below article, “Cystic Fibrosis protects against
tuberculosis”, from the magazine New Scientist. Then answer the following questions
Figure 1. Chest Radiograph of CF Diffuse Interstitial Disease
Image: http://www.eradimaging.com/site/article.cfm?ID=327: Reprinted with permission from LearningRadiology.com. Case of the Week Archives—2003. Cystic Fibrosis. Available at: http://www.learningradiology.com/toc/tocsubsection/tocarchives2003.htm. Accessed January 28, 2008.11
Connecting Genetics and Evolution:Cystic Fibrosis Case Study
Purpose: Discuss mutations and their possible effects Learn about the effects of mutations that cause cystic
fibrosis Analyze DNA sequences to determine if and what kind of
mutations exist Whole Class Work:
Read the Background Information and Supporting Information
Paired Work: Complete the Pre-Activity Questions Determine the genotypes and phenotypes of 4 people for
the CFTR protein to identify whether or not they have Cystic Fibrosis
Individual Work: Read the below article, “Cystic Fibrosis protects against
tuberculosis”, from the magazine New Scientist. Then answer the following questions
Connecting Genetics and Evolution:Cystic Fibrosis Case Study
Bio 9C: Tuesday, 4.26.11Title: Cystic Fibrosis, Tuberculosis and Evolution
Homework: Complete/ Revise Analysis Question 3 after today’s discussion. In your Notebooks:
Actively Read 16.1 with and put your reading notes in your notebook. THEN, complete questions 1, 2, 4, & 5 at the end of the chapter. Put these questions in your notebooks.
Do Now(s): On next three slides (clicker questions)
Today’s Objectives: Determine an organism’s genotype and phenotype by analyzing their DNA
sequences Explain how mutations can be passed on and why this is important
in evolution Explain why certain allele can become more common in certain
populations
Reviewing Background Info & HW
The CFTR protein is:
1 2 3 4
13% 13%13%
63%1. A gene2. A channel in cell
membranes3. A chloride ion4. An amino acid
Figure 1. Chest Radiograph of CF Diffuse Interstitial Disease
Image: http://www.eradimaging.com/site/article.cfm?ID=327: Reprinted with permission from LearningRadiology.com. Case of the Week Archives—2003. Cystic Fibrosis. Available at: http://www.learningradiology.com/toc/tocsubsection/tocarchives2003.htm. Accessed January 28, 2008.11
Connecting Genetics and Evolution:Cystic Fibrosis Case Study
Did you complete the genotype/ phenotype chart by analyzing the DNA sequences for all of 4 people?
1 2
21%
79%1. Yes2. No
Did you try to finish all of the reading and try to complete up to question 1?
1 2
11%
89%1. Yes2. No
Which of the children in the problem definitely has CF?
1 2 3 4
6%
56%
6%
33%
1. Fred2. Wilma3. Barney4. Betty
Reviewing CFTR Genotypes
DNA Analysis for the CFTR Protein Codon
504 Codon
505 Codon
506 Codon
507 Codon
508 Codon
509 Codon
510 Codon
511 Allele
F=Normal f=mutated
Genotype
FRED
Gene on Maternal Chromo
DNA CTT TTA TAG TAA AAG CCA CAA AGG
F
FF
mRNA GAA AAU AUC AUU UUC GGU GUU UCC
A.A.s GLU ACID
ASPAR-AGINE
ISOLEUCINE
ISOLEUCINE
PHENALYNINE
GLYCINE
VALINE SERINE
Gene on Paternal Chromo
DNA CTT TTA TAG TAG AAG CCA CAA AGG
F mRNA GAA AAU AUC AUC UUC GGU GUU UCC
A.A.s GLU ACID
ASPAR-AGINE
ISOLEUCINE
ISOLEUCINE
PHENALYNINE
GLYCINE
VALINE SERINE
WILMA
Gene on Maternal Chromo
DNA CTT TTA TAG TAA AGG CCA CAA AGG
F/f (?) Ff or ff
mRNA GAA AAU AUC AUU UCC GGU GUU UCC
A.A.s GLU ACID
ASPAR-AGINE
ISOLEUCINE
ISOLEUCINE
SERINE GLYCINE
VALINE SERINE
Gene on Paternal Chromo
DNA CTT TTA TAG TAA CCA CAA AGG
f mRNA GAA AAU AUC AUU GGU GUU UCC
A.A.s GLU ACID
ASPAR-AGINE
ISOLEUCINE
ISOLEUCINE
GLYCINE
VALINE SERINE
BARNEY
Gene on Maternal Chromo
DNA CTT TTA TAG TAA CCA CAA AGG
f
Ff
mRNA GAA AAU AUC AUU GGU GUU UCC A.A.s GLU
ACID ASPAR-AGINE
ISOLEUCINE
ISOLEUCINE
GLYCINE
VALINE SERINE
Gene on Paternal Chromo
DNA CTT TTA TAG TAA AAG CCA CAA AGG
F mRNA GAA AAU AUC AUU UUC GGU GUU UCC
A.A.s GLU ACID
ASPAR-AGINE
ISOLEUCINE
ISOLEUCINE
PHENALYNINE
GLYCINE
VALINE SERINE
BETTY
Gene on Maternal Chromo
DNA CTT TTA TAG TAA CCA CAA AGG
f
ff
mRNA GAA AAU AUC AUU GGU GUU UCC
A.A.s GLU ACID
ASPAR-AGINE
ISOLEUCINE
ISOLEUCINE
GLYCINE
VALINE SERINE
Gene on Paternal Chromo
DNA CTT TTA TAG TAA CCA CAA AGA
f mRNA GAA AAU AUC AUU GGU GUU UCC A.A.s GLU
ACID ASPAR-AGINE
ISOLEUCINE
ISOLEUCINE
GLYCINE
VALINE SERINE
Tuberculosis and the Evolution of the CF Gene
CF and Evolution
Read the article, “Cystic fibrosis gene protects against tuberculosis”
Respond to question 3
Based on the reading, why may people of European decent have a higher frequency of Cystic Fibrosis
1. The CF gene originated in Europe and only Europeans can pass it on to offspring
2. Having 1 copy of the CF gene may provide resistance to sickle cell anemia
3. Having 1 copy of the CF gene may provide resistance to tuberculosis
4. The CF gene does not have a higher frequency in Europeans
Objectives for Class:• Determine an organism’s genotype and phenotype by analyzing their DNA sequences• Explain the evolutionary connection between cystic fibrosis and tuberculosis
Block 2
Evolutionary Terms and Vocab
Some New Evolution Terms
Population Group of individuals from the same species that
interbreed Gene Pool
All the genes and all of their alleles in population Relative Frequency
The proportion of one allele in the whole gene pool Evolution (on a population scale)
Any change in the relative frequency of alleles over time One allele becomes more common, another becomes less common
Change in a population NOT change in an individual Fitness
The ability of a particular genotype to reproduce and pass on its genes to the next generationObjectives for Class:
• Use actual evidence to explain how the four principles of natural selection shape the evolution of organisms
Evolution Notes: Micro-Evolution
Small-scale Changes in a population’s gene pool over
time Caused by natural selection and/or
genetic drift
Example: CF allele becomes more common in European populations because it protects against tuberculosisObjectives for Class:
• Use actual evidence to explain how the four principles of natural selection shape the evolution of organisms
Large-scale, often over a very long time Branching of one species into two species Leads to the idea that all species share a
common ancestor
Example: Evolution of whales from four-legged land mammals
Micro-evolution leads to Macro-evolution
Evolution Notes: Macro-Evolution
Objectives for Class:• Use actual evidence to explain how the four principles of natural selection shape the evolution of
organisms
How Do Populations Evolve?
Natural Selection: Certain genotypes/phenotypes are more
“fit” than others, and pass on more of their genes to the next generation
Over time, those “fit” genes become more common in the whole population because they are more helpful for survival and reproduction
Complete HW
In your Notebooks: Actively Read 16.1 with and put your
reading notes in your notebook. THEN, complete questions 1, 2, 4, & 5 at the end of the chapter. Put these questions in your notebooks.
Bio 9B: Wednesday, 4.27.11Title: Evidence for Natural Selection
Homework: Pass Cystic Fibrosis Case Study to the left Write a paragraph in your notebook that explains each of the
following terms and how they relate to each other: population gene pool alleles evolution in populations natural selection
Do Now(s): Next slide
Today’s Objectives: Explain how natural selection can cause an allele to
become more common in a population’s gene pool over time.
Did you try to finish all of the reading and try to complete all of the 3 questions?
1 2
20%
80%1. Yes2. No
Based on the reading, why may people of European decent have a higher frequency of Cystic Fibrosis
1 2 3 4
6%0%
94%
0%
1. The CF gene originated in Europe and only Europeans can pass it on to offspring
2. Having 1 copy of the CF gene may provide resistance to sickle cell anemia
3. Having 1 copy of the CF gene may provide resistance to tuberculosis
4. The CF gene does not have a higher frequency in Europeans
Objectives for Class:• Determine an organism’s genotype and phenotype by analyzing their DNA sequences• Explain the evolutionary connection between cystic fibrosis and tuberculosis
Recap and Review: Cystic Fibrosis and Tuberculosis
Recessive Genetic Disorder Result of a gene mutation in the CFTR protein
Numerous types of mutations – most common is deletion of 1 amino acid at Codon 508
Evidence suggests people who are homozygous recessive and heterozygous are resistant to tuberculosis TB bacteria need a nutrient that these people do not make
When TB killed 20% of Europeans from 1600-1900, people who are heterozygous for CF gene survived to pass on the gene Allele persists, despite people who are homozygous
recessive not reaching adulthood Objectives for Class:• Determine an organism’s genotype and phenotype by analyzing their DNA sequences• Explain the evolutionary connection between cystic fibrosis and tuberculosis
Finches on the Galapagos Islands
Evidence for Natural Selection
Galapagos Finch Investigation
Evidence for Natural Selection: Finches on the Galapagos Islands
Objectives for Class:• Use actual evidence to explain how the four principles of natural selection shape the evolution of
organisms
Bio 9B: Thursday, 4.28.11Title: Review of Natural Selection
Homework: Complete Natural Selection Review Packet
Do Now: Next Slide – Log in with clicker
Today’s Objectives: Explain the process of natural selection Apply the principles of natural selection in order to
analyze a variety of examples
Starting in 1954 commercial fishers were paid by weight, rather than by the individual fish for pink salmon. The fishers used the type of net that selectively catches larger fish. Which of the following is the most likely effect of this technique on salmon populations over the next 20 years?
1 2 3 4
10%0%0%
90%1. The average body size of the
salmon population increased significantly.
2. The average body size of the salmon population decreased significantly.
3. The average body size of the males increased and the females stayed the same.
4. The average body size of the males stayed the same and the females increased.
Agenda • Complete Galapagos Finch Investigation (25 min)• (enrichment extra credit if completed early and all other assignments are complete)
• Principles of Natural Selection review and second case study
Galapagos Finch Investigation
Evidence for Natural Selection: Finches on the Galapagos Islands
Objectives for Class:• Use actual evidence to explain how the four principles of natural selection shape the evolution of
organisms
Recap and Review: Evidence for Natural Selection in Galapagos Finches
Drought causes declines in the food supply between 1976-1978
Objectives for Class:• Use actual evidence to explain how the four principles of natural selection shape the evolution of
organisms
Variety of seeds declines and only tough seeds with thick shells are left.
Only those finches with thicker beaks can eat. Finches with narrower beaks can’t eat and die.
Result: Relative frequency larger beak sizes increase, because birds with bigger beaks survive and reproduce. The alleles for larger beak size have greater fitness!
Agenda • Principles of Natural Selection review and second case study
More Evidence for Natural Selection: Hummingbird Populations Scientists studying natural selection in
Hummingbird Populations in Ecuador:
http://www.pbs.org/wgbh/evolution/library/11/2/e_s_4.html
Objectives for Class:• Use actual evidence to explain how the four principles of natural selection shape the evolution of
organisms
Principles of Natural Selection
“Selection” is different survival and reproduction of individuals with
different genotypes Natural selection involves…
Genetic variation between individuals in the species and/or population
More offspring are born than can survive Competition/struggle for survival for limited resources Variation between individuals that makes some better
able to survive and reproduce than others This variation is heritable/genetic (can be passed on)
Result: Over many generations, the genotypes that are better able to survive and reproduce become more common in the population.
Summarizing Natural Selection in the Hummingbird Case Study In your notebooks:
Take five minutes to summarize how the 4 principles of Natural Selection are demonstrated in the hummingbird case study you just watched.
Use specific examples from the film to describe each principle
Four Principles: Genetic Variation Over-production of Offspring Struggle for Existence Differentiated Survival
Bio 9B: Monday, 5.2.11Title: Review of Natural Selection
Homework: Reading from Section 16-3:
Read pages 404-405 and take notes on: What is speciation? What is reproductive isolation? What are some
different ways that populations can be reproductively isolated?
Read pages 408-409 and take notes on: What are the steps of speciation?
Do Now: Next Slide – Log in with clicker
Today’s Objectives: Explain the process of natural selection Apply the principles of natural selection in order to analyze a variety of
examples
1. Which statement is the BEST description of the theory of evolution by natural selection?
A. B. C. D.
0% 0%0%0%
A. When environmental conditions are challenging for a population, some individual organisms mutate in order to get the traits that will help them survive the best.
B. The organisms that are the strongest and fastest always survive the longest.
C. In populations, some individuals have combinations of genes that allow them to survive and reproduce better, which causes these gene combinations to spread through the whole population over many generations.
D. Humans evolved from a species of apes because humans have longer life spans than apes.
0
5
Review Principles of Natural Selection
“Selection” is different survival and reproduction of individuals with
different genotypes Natural selection involves…
Genetic variation between individuals in the species and/or population
More offspring are born than can survive Competition/struggle for survival for limited resources Variation between individuals that makes some better
able to survive and reproduce than others This variation is heritable/genetic (can be passed on)
Result: Over many generations, the genotypes that are better able to survive and reproduce become more common in the population.
Two Sources of Genetic Variation Mutations
Any change to a DNA sequence Rare Sometimes harmful, sometimes helpful
Mutations to egg or sperm = passed on to offspring Mutations to body cells = not passed on (but can
cause CANCER)
Gene Shuffling Meiosis divides the genetic info and fertilization
recombines it 23 pairs of chromosomes = 8.4 million different
combinations of genes!
Crossing Over during meiosis increases the number of different combinations of alleles
Objectives for Class:• Explain the process of natural selection• Apply the principles of natural selection in order to analyze a variety of examples
More Evidence for Natural Selection: Antibiotic Resistance in TB Bacteria
Bacteria populations can evolve too! Let’s watch and see how people influence
evolution in bacteria… http://www.pbs.org/wgbh/evolution/library/10/4/l_104_09.html
In your Notebook: How does the TB bacteria experience natural
selection. How did population of bacteria change over
time, and why? How is this similar to the Hummingbird and
Finch case studies?
Objectives for Class:• Explain the process of natural selection• Apply the principles of natural selection in order to analyze a variety of examples
Clicker Review of Natural Selection
2. Which of the following factors has the greatest effect on whether the new coat color will become more common in the mouse population?
A. B. C. D.
0% 0%0%0%
A. Whether abundant food is available in the grassland
B. Whether the new coat color allele is dominant or recessive
C. Whether the rate of reproduction in the mouse population is stable
D. Whether the new coat color allele increases the survival and reproduction of mice in their environment
0
5
3. The long tail feather trait is maintained in the barn swallow population because, compared to males with a shorter tail feather, males with a longer tail feather are more likely to:
A. B. C. D.
0% 0%0%0%
A. Build a large nestB. Produce offspringC. Migrate each winterD. Escape from predators.
0
5
4. Which biological concept is being illustrated in the diagrams of the lizard population?
A. B. C. D.
0% 0%0%0%
0
5
A. Polygenic traitsB. Natural selectionC. Sex-linked inheritanceD. Silent mutations
5. Which of the following best explains why, in environments with long flowers, hummingbirds tend to have long beaks?
A. B. C. D.
0% 0%0%0%
0
5
A. Hummingbirds with long beaks can reach their food better, and therefore they have more energy to survive and pass on their genes for long beaks.
B. Hummingbirds with long beaks are better at attracting mates than hummingbirds with short beaks.
C. Hummingbirds stretch their beaks in order to reach the food at the bottom of the long flowers, so after lots of stretching, all the birds have long beaks.
D. Hummingbirds with long beaks are better able to fight off predators than hummingbirds with short beaks.
6. Which of the following best explains the increase in drug-resistant TB bacteria?
A. B. C. D.
0% 0%0%0%
0
5
A. The bacteria that are resistant to the drugs mate with each other to produce super-resistant bacteria that have twice as many copies of the resistance genes.
B. TB bacteria only infects people who are already malnourished and sickly, and the bacteria draws strength from the infected people in order to become resistant to their medicines.
C. When anti-TB drugs are taken in low doses, the drugs kill the most susceptible bacteria but don’t kill the more resistant bacteria. The more resistant bacteria reproduce and pass on their resistance genes so that the whole population becomes resistant to the drugs.
D. When a patient begins taking anti-TB drugs, the bacteria mutate in order to become resistant and fight off the drugs.
7. Which of the following is a result of the limited genetic variation in the current cheetah populations compared to earlier cheetah populations with more variation?
A. B. C. D.
0% 0%0%0%
0
5
A. Cheetahs in current populations are more resistant to new diseases.
B. The survival rate of young cheetahs is increased in current populations.
C. Cheetahs in current populations are less able to interbreed with other species.
D. The current cheetah populations are less likely to be able to adapt to environmental changes.
Natural Selection in the Squirrel Population! Example 1: New Environment with Light
Gray Soil
Example 2: New Environment with Light and Dark Gray Rocks
Begin Speciation HW
Reading from Section 16-3:Read pages 404-405 and take notes on:
What is speciation?What is reproductive isolation? What are some different ways that populations can be reproductively isolated?
Read pages 408-409 and take notes on:What are the steps of speciation?
Bio 9B: Tuesday, 5.3.11Title: Block 1 - Speciation
Homework: Complete Part A of the Evolution
Investigation: All in the Family
Do Now: Next Slide – Log in with clicker
Today’s Objectives: Explain the process of natural selection Apply the principles of natural selection in order to
analyze a variety of examples
Speciation
SPECIES
A group of similar organisms
Breed with each other Produce Viable Offspring
Objectives for Class:• Explain the defining characteristics of a species• Describe the 2 steps of speciation
Speciation
The formation of new species
The gene pools of two populations must become separated
Ex: The Galapogos Finches
Objectives for Class:• Explain the defining characteristics of a species• Describe the 2 steps of speciation
Steps of Speciation
1. Reproductive Isolation
2. Changes in the Gene Pool Gene Pools Diverge Genetic Barriers to
Reproduction
Objectives for Class:• Explain the defining characteristics of a species• Describe the 2 steps of speciation
Reproductive Isolation
One population becomes isolated from the rest of the species
1. Behavior: Changes in courtship or other reproductive
strategies
2. Geographic Geographic barrier splits population (i.e.: river,
mountain, body of water, etc.) Populations are separated and cannot
interbreed Conditions of their local environment select
certain traits
3. Temporal Species reproduce at different times or have
other behavior that becomes time sensitive (i.e.: feeding)
Objectives for Class:• Explain the defining characteristics of a species• Describe the 2 steps of speciation
Changes in the Gene Pool
1. Gene Pools Diverge: The isolated populations become genetically different. Due to selection and/or genetic drift Two separate gene pools emerge
2. Genetic Barriers to Reproduction The two populations are no longer able to interbreed Due to genetic differences in habitat preference,
mating behavior, or physical compatibility Competition may arise between these two new
species
They are now two separate species!Objectives for Class:• Explain the defining characteristics of a species• Describe the 2 steps of speciation
Reproductive Barriers That Maintain Separate Species
Before mating occurs Geographic barriers Ecological/habitat differences Temporal differences Behavioral/courtship differences Mechanical differences Chemical differences
After mating occurs Hybrid inviability Hybrid breakdown Hybrid sterility
Objectives for Class:• Explain the defining characteristics of a species• Describe the 2 steps of speciation
Famous Hybrids (what happens when two species come together)
Move to “Evidence for Evolution Presentation” for Block 2