bio 9b: tuesday, 3.22.11 title: introduction to genetic inheritance and variation
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Bio 9B: Tuesday, 3.22.11 Title: Introduction to Genetic Inheritance and Variation. Double Block. Homework: Complete the Making Babies Analysis Questions Silent Do Now: (in notebook w/ title and date) - PowerPoint PPT PresentationTRANSCRIPT
Bio 9B: Tuesday, 3.22.11Title: Introduction to Genetic Inheritance and Variation
Homework: Complete the Making Babies Analysis Questions
Silent Do Now: (in notebook w/ title and date) What is the difference between a gene and an allele? (Check
your notes from last week if you don’t remember) How do you think a dominant allele is different from a recessive
allele? What do you think dominant and recessive mean? Predict what you think genotype and phenotype mean (these
are new words we will learn today) Hand in Modeling Meiosis packet and Karyotyping Part II packet if
you didn’t hand them in yesterday Today’s Objectives:
Use genetics vocabulary to describe genes and alleles Differentiate between genotypes and phenotype Experiment with probability to see the diversity of offspring that
can be made through sexual reproduction
Double Block
Introduction to new Genetics Terms (10 min) Makin’ Babies Activity
Explanation (5 minutes) Activity (25 minutes)
Post picture of the Baby on the front board Introduction to Punnett Squares/ Monohybrid Crosses (15 Min)
Making Babies Probability w/ clickers (15 min) Making Babies Analysis Questions (20 min)
Agenda
MENDELIAN GENETICS:THE STUDY OF GENETIC INHERITANCE PATTERNSBiology 9: Moretti / Dickson
Genetics Overview Genetics is the study of gene inheritance
and variation
Genetics answers big questions like: How are traits inherited? Why do offspring look similar to their
parents but not exactly like their parents? How do we have so many different types of
organisms and so much genetic variation? Objectives for Class:• Experiment with probability to see the diversity of offspring that can be made through sexual
reproduction
Genetics Vocabulary:Gene:
A section of DNA that encodes a particular protein (ex: hair protein)
Alleles:Different versions of a gene (ex: black hair vs.
blond hair)Everyone has two alleles for each gene – one from each parent!
New Vocabulary: Dominant and Recessive
Dominant: The allele that is always expressed as a trait if it is
present (regardless of other alleles) Recessive:
The allele that is only expressed as a trait if the dominant allele is not present
Mendelian Genetics and Probability
Objectives for Class:• Experiment with probability to see the diversity of offspring that can be made through sexual
reproduction
Evidence:True-breeding yellow x True-breeding green
(YY) (yy) All yellow offspring (Yy)
New Vocabulary: Genotypes and Phenotypes
Genotypes: The genetic make-up of an organism The combination of alleles
Phenotypes: The expressed physical
characteristics The “Trait”
“Phenotypes are the sum of Genotypes + Environment”
Mendelian Genetics and Probability
Objectives for Class:• Experiment with probability to see the diversity of offspring that can be made through sexual
reproduction
“Makin’ Babies”:Mendelian Genetics and Probability
Step 1: Genotype Data Table”Determine the Traits of your baby by flipping the coin a total
of two times for each trait (once for each allele). Heads = Dominant and XTails = Recessive and Y
Example: Face shape = R, so heads=R and tails = rWrite the combination of the alleles in the box next to the trait. This is the Genotype for each trait
Step 2: Phenotype chartDetermine the Phenotype based on the Genotype from page 1Example: if you flipped two RR for face shape, the phenotype would be Round
Step 3: Draw your baby by using the traits from the Phenotype chart
Homozygous and Heterozygous Homozygous: Two of the same allele
for a particular trait are presentEx: RR (homozygous dominant) = Round
FaceEx: rr (homozygous recessive)= Square Face
Heterozygous: Two different alleles for a particular trait are presentEx: Rr = Round Face
More Genetics Vocabulary
Objectives for Class:• Experiment with probability to see the diversity of offspring that can be made through sexual
reproduction
Making Babies – Predicting Probabilities
In the activity, the mother and father were both heterozygous for each trait
Mother was Rr Father was Rrhalf of the sperm got each
allele½ of Mom’s eggs got the R allele
½ of Mom’s eggs got the r allele
R
r
rRRR
rr
Rr
Rr
Making Babies – Predicting Probabilities
This Punnett Square is used to PREDICT PROBABILITIES, NOT to tell you the actual numbers you will get!
Probability of Round Face (RR or Rr) = ¾ or 75%
Probability of Square Face (rr)= ¼ or 25%
R
r
rRRR
rr
Rr
Rr
Now let’s make predictions for the sex of the baby (boy or girl?)
Mother’s genotype: Father’s genotype: Make a Punnett Square and fill it in
Chances of girl (XX)
= ½ or 50%
Chances of boy (XY)
= ½ or 50%
X
YX
X
XX
XY
XY
XX
XXXY
Your Clicker Number:Write it on the FRONT of your notebook
Clicker Number
Student Name
1 Israel 2 Patrick 3 Trevon 4 Jamesley 5 Nancy 6 Zuri 7 Andre 8 McHenley 9 Aser 10 Emily 11 Harold 12 Natalie
Clicker Number
Student Name
13 Ricardo14 Whitney 15 Grace 16 Thomas17 Natalie 18 Leslie19 Emperor20 Julian 21 Larissa
Take out the Making Babies packet and turn to the very back page
We will use clickers to collect data for Analysis Question #5
Calculate Expected Ratios for the following traits
Now let’s see if the class’s babies match our predicted probabilities!
TraitEXPECTED Ratio
PERCENT of Babies with Dominant Phenotype
PERCENT of Babies with Recessive Phenotype
Face Shape 75%, 25%
Cleft Chin 75%, 25%Widow’s Peak 75%, 25%
Earlobes 75%, 25%Gender 50%, 50%
Phenotype Class Results:What is the face shape of your baby?
1 2
24%
76%1. Round (dominant)
2. Square (recessive)
Objectives for Class:• Experiment with probability to see the diversity of offspring that can be made through sexual
reproduction
1 2
14%
86%
Phenotype Class Results:Does your baby have a cleft chin? 1. No, it’s absent
(dominant)2. Yes, it’s present
(recessive)
Objectives for Class:• Experiment with probability to see the diversity of offspring that can be made through sexual
reproduction
Phenotype Class Results:Does your baby have a widow’s peak?
1 2
36%
64%1. Yes, it’s present
(dominant)2. No, it’s absent
(recessive)
Objectives for Class:• Experiment with probability to see the diversity of offspring that can be made through sexual
reproduction
Phenotype Class Results:What kind of earlobes does your baby have?
1 2
18%
82%1. Unattached
(dominant)2. Attached
(recessive)
Objectives for Class:• Experiment with probability to see the diversity of offspring that can be made through sexual
reproduction
Phenotype Class Results:What is the gender of your baby?
1 2
41%
59%1. Girl (XX)2. Boy (XY)
Objectives for Class:• Experiment with probability to see the diversity of offspring that can be made through sexual
reproduction
Take out the Making Babies packet and turn to the very back page
We will use clickers to collect data for Analysis Question #5
Now let’s see if the class’s babies match our predicted probabilities!
TraitEXPECTED Ratio
PERCENT of Babies with Dominant Phenotype
PERCENT of Babies with Recessive Phenotype
Face Shape 75%, 25%
Cleft Chin 75%, 25%Widow’s Peak 75%, 25%
Earlobes 75%, 25%Gender 50%, 50%
Making Babies – Analysis Questions Answer all questions on a separate piece
of paper This is HW due tomorrow!
Bio 9B: Wednesday, 3.23.11Title: No Class – Half Day
Homework:
Do Now:
Today’s Objectives:
Bio 9B: Thursday, 3.24.11Title: Genetic Inheritance & Variation - Mendel’s Principle of Segregation
Homework: Complete the remaining questions from the Monohybrid Crosses
Worksheet Also, read pgs 267-273 and complete the “Reviewing Mendel’s 4
Principles of Genetic Inheritance” guide. Additionally, review key vocabulary that we have gone over in class and be sure to have the terms explained in your notebook.
Do Now: Get a clicker and answer the questions on the following slides You will need the Making Babies Analysis Questions
Today’s Objectives: Use Mendel’s Principle of Segregation to explain: How can children show
traits that their parents don’t have? Use Punnett Squares to solve monohybrid crosses
Do Now: Which of the following terms applies to traits, such as eye color, that are controlled by more than one gene?
1 2 3 4
5% 5%0%
90%1. Codominant2. Polygenic 3. Recessive4. Dominant
Pass Making Babies to the left!
Vocabulary Review
DO NOW: Does this picture show GENOTYPES or PHENOTYPES? “Click” your answer…
A. B.
76%
24%
A. GenotypesB. Phenotypes
Objectives for Class:• Differentiate between genotypes and phenotypes
Vocabulary Review Genotype:
genetic make-up/combination of alleles (Ex: AA, Aa, or aa)
Phenotype: The traits that an organism has
(Ex: purple flowers or white flowers)
Trait: a specific characteristic that
varies between individuals (Ex: flower color)
Objectives for Class:• Differentiate between genotypes and phenotypes
Vocabulary Review Fill in the blanks…
Which allele is dominant? Recessive? How do you know? Purple (A) = Dominant White (a) = Recessive
What is the phenotype?
What is the phenotype?
What is the genotype?
Objectives for Class:• Differentiate between genotypes and phenotypes
New(ish) Vocabulary Fertilization:
the joining of two gametes in sexual reproduction
Zygote: a fertilized egg cell that
will grow and develop into an offspring
A human zygote, like most other human cells, contains 46 chromosomes. How many chromosomes does the a zygote receive from the mother?
1 2 3 4
0% 0%0%
100%1. 122. 233. 464. 92
In the diagram below, which process is fertilization?
1 2
5%
95%1. Process A2. Process B
Monohybrid Punnett Square Practice
In guinea pigs, rough coat (R) is dominant over smooth coat (r). A heterozygous guinea pig is mated with another heterozygous pig.What percentage of the next generation will have smooth coat?
1 2 3 4
0% 0%
100%
0%
1. 100%2. 50%3. 25%4. 75%
Introduction to Mendelian Genetics
Some background on Mendel and what he did to advance genetics
You Don’t need to write this down: Gregor Mendel studied
genetics by doing experiments with pea plants.
He started with true-breeding plants, which he knew were homozygous for their traits.
Objectives for Class:• Use Mendel’s Principle of Segregation to explain: How can children show traits that their parents don’t have?
• Use Punnett Squares to solve monohybrid crosses
Objectives for Class:• Use Mendel’s Principle of Segregation to explain: How can children show traits that their parents don’t have?
• Use Punnett Squares to solve monohybrid crosses
You don’t need to write this down: Gregor Mendel studied genetics by
doing experiments with pea plants. He started with true-breeding plants,
which he knew were homozygous for their traits.
When he cross-bred these plants, he found that one phenotype was dominant over the other.
But when he cross-bred the offspring, the recessive phenotype reappeared!
How can we explain this??
Some background on Mendel and what he did to advance genetics
CW/ HW Monohybrid Crosses Complete Question 1 (you will need to reference a
book In sheep, the allele for black wool (a) is
recessive and the allele for white wool (A) is dominant. Imagine that two white sheep that are heterozygous mate with each other to produce lambs. Trace the alleles for each parent through
diagrams of Meiosis. Show the positions of the alleles on the chromosomes at: Metaphase I, Metaphase II, and at the end of meiosis. (In other words, draw the chromosomes & the alleles!)
Review Principle of Segregation
Mendel’s Discoveries: Principle of Segregation Alleles segregate (separate)
during meiosis so each gamete gets one allele
a a A A
a Aa A
Two choices for gametes:A or a
Volunteer to Draw Punnett Square? 1c
Draw a Punnett Square showing the possible results of 2 heterozygous white sheep mating
Principle of Segregation (continued…)
This explains why the recessive trait reappears in the F2 generation…
In ¼ of the offspring.Source
of Gametes
Review: Principle of Segregation and Meiosis
AA
AaAaAaAa
A aA a
aaOriginal Diploid
Cells
Segregation
Fertilization
Possible Haploid
Gametes
Possible Diploid Zygotes
CW/ HW Monohybrid Crosses Complete Questions 2 – 4
Bio 9B: Monday, 3.28.11Title: Dihybrid Crosses and Mendel’s Principle of Independent Assortment
Homework: Complete the remaining questions from the
Dihybrid Crosses Worksheet
Do Now: What are Mendel’s 4 Principles of Genetic
Inheritance?
Today’s Objectives: Use Punnett Squares to solve dihybrid crosses Use Mendel’s Principle of Independent Assortment to explain
how genetic variation is created in individuals.
• Pass Back Work •Review HW• Review Mendel’s 4 Principles of Inheritance• Principle of Independent Assortment and DiHybrid Crosses
AGENDA
Question 2 (d): What is the probability of purple flowers?
1 2 3 4
0% 0%
79%
21%
1. 25%2. 50%3. 75%4. 0%
Question 3 (C): If Ben and Jaelene has a child, what is the probability s(he) will have attached earlobes?
1 2 3 4
32%
0%
11%
58%1. 25%2. 50%3. 75%4. 0%
Question 4 (b): A cross between a cow and a bull that both have red and white spots. What are the probabilities of a red calf?
1 2 3 4
74%
0%5%
21%
1. 25%2. 50%3. 75%4. 0%
Review Mendel’s Principles of Inheritance
Genes in Pairs: Traits are controlled by genes that occur with two
different forms (alleles) Principle of Dominance:
Some alleles are dominant and others are recessive
Principle of Segregation: The two alleles for a gene segregate (separate)
during meiosis so each gamete gets one allele Principle of Independent Assortment (new):
Alleles for different genes separate independently during meiosis.
What is one difference between these two cells?
Which chromosome is homologous to this one? If we looked at human cells, how many pairs of
homologous chromosomes would they contain? Answer: 23 pairs (22 pairs plus the sex chromosomes)
aaA A
b b
BB
a a A A
Cell 1 Cell 2
AB
A A aa
b bBB
A A aa
b b BB
AB
ab
ab
or…
aB
Ab
aB
Ab
Four different possible gametes:AB ab Ab aB
Alleles for different genes separate independently during meiosis.
In other words: If a gamete gets A or a, this doesn’t effect whether it gets B or b. Any combo is possible:Parent: AaBb
Possible gametes: AB Ab aB ab
This creates genetic diversity between gametes, and therefore a greater diversity of offspring.
Mendel’s Discoveries: Principle of Independent Assortment
Objectives for Class:• Use Punnett Squares to solve dihybrid crosses• Use Mendel’s Principle of Independent Assortment to explain how genetic variation is
created in individuals.
Example: Dihybrid Cross(only write what’s in purple)
Unattached earlobe (E) is dominant over attached earlobe (e)
Black hair (B) is dominant over blond hair (b) Two parents are heterozygous for both traits:
(1) Write the parent genotypes: EeBb x EeBb(2) What possible gametes can they each make?
E e B bEB
Eb
eB
eb
Unattached w/ Black hair = Unattached w/ Blond hair =
(3) Write the gametes along the left side and top of a BIG Punnett Square (4 x 4)
(4) Use the Punnett Square to calculate probabilities!
EB
Eb
eB
eb
EB Eb eB eb
EEBb
EeBB
EeBb
EEBB
Eebb
EeBb
EEbb
EEBb EeBB
EeBb
eeBB
eeBb eebb
eeBb
Eebb
EeBb
Attached w/ Black hair = Attached w/ Blond hair = 1/16
9/163/16
3/16
What is the probability of having a baby with attached earlobes and black hair?
1 2 3 4
0% 0%0%0%
1. 1/162. 8/163. 3/164. 12/16
0
5
Complete Dihybrid Worksheet Questions 1-2
example: dihybrid cross
Bio 9B: Tuesday, 3.29.11Title: Genetic Inheritance & Variation - Mendel’s Principle of Independent Assortment
Homework:
Do Now:
Today’s Objectives: Use Punnett Squares to solve dihybrid crosses Use Mendel’s Principle of Independent Assortment
to explain how genetic variation is created in individuals.
Did you complete the DiHybrid HW
1 2
0%0%
1. Yes2. No
0
5
1b. Suzy’s genotype is…?
1 2 3 4
0% 0%0%0%
1. Rr2. Ry3. RrYy4. RRyy
0
5
1b. Suzy’s possible gametes are:
1 2 3 4
0% 0%0%0%
1. RR, YY, rr, yy2. RY, Ry, rY, ry3. RY, RY, ry, ry4. R, Y, r, y
0
5
1d. The probability of round, green seeds is:
1 2 3 4
0% 0%0%0%
1. 1 out of 42. 3 out of 43. 3 out of 164. 9 out of 16
0
5
2. Rakim’s phenotype is (you will need to think about this one!)
1 2 3 4
0% 0%0%0%
1. LlBb2. LbLb3. Flat chin, bent
pinkies4. Cleft chin, bent
pinkies
0
5
2. Rakim’s genotype is:
1 2 3 4
0% 0%0%0%
1. LlBb2. LbLb3. Bb4. LB
0
5
2. Rakim and Jennifer could both make which gametes?
1 2 3 4
0% 0%0%0%
1. Ll, Bb, ll, bb2. LB, Lb, lB, lb3. L, B, l, b4. L or B
0
5
2. What is the probability that their child will have a cleft chin and bent pinkies?
1 2 3 4
0% 0%0%0%
0
5
1. 1 out of 42. 1 out of 163. 3 out of 44. 9 out of 16
2. What is the probability that their child will have a flat chin and straight pinkies?
1 2 3 4
0% 0%0%0%0
5
1. 1 out of 42. 1 out of 163. 3 out of 44. 9 out of 16
3. What is Charlie’s genotype?
1 2 3 4
0% 0%0%0%0
5
1. LLBB2. LlBb3. Llbb4. llbb
3. Why is the Punnett Square only 1 by 4?
1 2 3 4
0% 0%0%0%
0
5
1. Because Jennifer and Charlie only had 1 child.
2. Because Charlie has a genetic mutation.
3. Because Charlie can only make one type of gamete.
4. Because Charlie doesn’t have very much sperm.
3. What is the probability of a child with a flat chin and bent pinkies?
1 2 3 4
0% 0%0%0%
0
5
1. 1 out of 42. 2 out of 43. 3 out of 44. 1 out of 16
Today’s Classwork Practice Test
Work on your own or quietly with your table partner
If you finish at least 10 questions in class with GOOD explanation, you get a treat
Earn more points for staying focused (and lose them for distracting yourself or others)
Please, I want to award points! Do your work!
This will prepare you for the test we’ll have next TUESDAY and will tell me what you still don’t understand.
Bio 9C: Tuesday, 3.29.11Title: Case Study: Albinism in the Bowman Family
Homework: None (or, if you didn’t finish the Genetics Practice test, finish it!)
Silent Do Now: (in NB w/ title and date) Brainstorm what you know and what questions
you have about albinism (this refers to people who are albino).
Today’s Objectives: Analyze a family’s genetic traits in order to…
Construct a pedigree diagram Determine if a trait is dominant, recessive, or codominant
The Bowman Family (8 years ago)
The Bowman Family (more recent)
A Pedigree Diagram
Bio 9B: Wednesday, 3.30.11Title: Case Study: Albinism in the Bowman Family – Day 2
Homework: Complete through question 4 (this includes the pedigree,
the column for albinism and the questions associated with albinism).
The project is due at the start end of the first half of the double block tomorrow.
Silent Do Now: (in NB w/ title and date) What questions still remain about albinism?
Today’s Objectives: Analyze a family’s genetic traits in order to…
Construct a pedigree diagram Determine if a trait is dominant, recessive, or codominant
Guidelines for working today: Work alone to write your Background
Info paragraph You may choose to work with one
partner after that. No groups bigger than 2!
You must ask permission to work at a back table. Some people will work at the front desks.
A Pedigree Diagram
Bio 9B: Wednesday, 3.31.11Title: Case Study: Albinism in the Bowman Family – Day 3
Homework: Study for the Test!
Silent Do Now: (be honest here… ) On the front of Albinism Case Study, if you were able to identify the
genotypes for albinism for the members of the Bowman Family, then put the letter “F” on the front of your case study.
If you struggled with this task, then put the letter “S” on the front of the packet
If you did not attempt it, put the letter “A” on the front of the paper
Today’s Objectives: Analyze a family’s genetic traits in order to…
Construct a pedigree diagram Determine if a trait is dominant, recessive, or codominant
Completing the Bowman Pedigree
Question 5: Dark brown hair (D) is dominant over light brown hair
(d). Blue eyes (e) are recessive, so anyone with another color has at least one dominant allele (E). In the table on page 4, fill in the final column of genotypes for hair color
and eye color for all family members except those with albinism. (Hint: start with Peter! Then figure out the parents, and then fill in everyone else.)
Make a Punnett square showing predicted ratios of genotypes and phenotypes for hair and eye color in the Bowman children, based on their parents’ genotypes.
How closely do the actual numbers of children match these predictions? Question 6: Michael (the 2nd Bowman child) is married to Alysia.
Alysia is of Chinese descent, so she has black hair and dark brown eyes. They do not have any children yet.
Block One
Genetics Test Review 5 Minutes Individual/ Silent Work
Complete Part I of the Review Packet When completed, look over the vocab in Part II and the
practice problems in Part III and Part IV. If you feel confident with your ability to complete ALL of the
problems, then put the letter “C” on the front of your review packet
If you feel confident with all of the problems except for the Dihybrid cross problems, then put the letter “D” on the front of your review packet
If you feel confident with the vocab, but not the Monohybrid and Dihybrid problems, the put the letter “M” on the front of the packet
If you don’t feel confident with most of the content of the review packet, the put the letter “A” on the front of the packet
Block Two
Genetics Review Divide into sections of the class based
on letters. M’s and D’s in the front seats C’s at the back tables A’s at the front tables
Block Two