bio 9b: tuesday, 3.22.11 title: introduction to genetic inheritance and variation

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

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

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

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%

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%

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?

76%1. Round (dominant)

2. Square (recessive)

reproduction

Phenotype Class Results:Does your baby have a cleft chin? 1. No, it’s absent

(dominant)2. Yes, it’s present

(recessive)

reproduction

Phenotype Class Results:Does your baby have a widow’s peak?

64%1. Yes, it’s present

(dominant)2. No, it’s absent

(recessive)

reproduction

Phenotype Class Results:What kind of earlobes does your baby have?

82%1. Unattached

(dominant)2. Attached

(recessive)

reproduction

Phenotype Class Results:What is the gender of your baby?

59%1. Girl (XX)2. Boy (XY)

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. 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)

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 genotype?

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?

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

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

AaAaAaAa

A aA a

aaOriginal Diploid

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

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

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

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)

a a A A

Cell 1 Cell 2

A A aa

b b BB

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

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

EEBb EeBB

eeBb eebb

Attached w/ Black hair = Attached w/ Blond hair = 1/16

9/163/16

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

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. Yes2. No

1b. Suzy’s genotype is…?

1 2 3 4

0% 0%0%0%

1. Rr2. Ry3. RrYy4. RRyy

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

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

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

2. Rakim’s genotype is:

1 2 3 4

0% 0%0%0%

1. LlBb2. LbLb3. Bb4. LB

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

2. What is the probability that their child will have a cleft chin and bent pinkies?

1 2 3 4

0% 0%0%0%

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

3. What is Charlie’s genotype?

1 2 3 4

0% 0%0%0%0

1. LLBB2. LlBb3. Llbb4. llbb

3. Why is the Punnett Square only 1 by 4?

1 2 3 4

0% 0%0%0%

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%

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?

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

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

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