bio 9c: thursday, 3.17.11 title: introduction to genetic inheritance and variation

Bio 9C: Thursday, 3.17.11Title: Introduction to Genetic Inheritance and Variation

Homework: Give me your Notebooks at the end of class (After the Do

Now and the Genetics Overview)!!!! Finish drawing your baby and answering Analysis questions

1-3 on a separate sheet of paper to be handed in!

Do Now: How can an error in meiosis result in abnormal chromosome

numbers in people? Nondisjunction Videos

Today’s Objectives: Describe the two ways meiosis creates genetic diversity between

gametes Experiment with probability to see the diversity of offspring that

can be made through sexual reproduction

Double Block

http://www.mtholyoke.edu/courses/rfink/Videopages/index.htm


Karyotyping Activity – Part II ReviewNondisjunction Videos



MENDELIAN GENETICS &GENETIC INHERITANCEBiology 9Moretti and Dickson

Genetics Overview The study of gene inheritance and

variation 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

Mendelian Genetics and Probability New Vocabulary:

Dominant and Recessive Genotypes and Phenotypes Homozygous and Heterozygous


reproduction

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


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”



reproduction

New Vocabulary: Homozygous and Heterozygous

Homozygous: Two of the same allele for a particular trait are present

Ex: RR = Round Face Ex: rr = Square Face

Heterozygous: Two different alleles for a particular trait are present

Ex: Rr = Round Face



reproduction

“Makin’ Babies”: Mendelian Genetics & Probability

Use the “Genotype Data Table” to 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 X Tails = Recessive and Y

For example: Face shape = R, so heads=R and tails = r Write the combination of the alleles in the box next to the trait. This is the

Genotype for each trait Then, go to the Phenotype chart

Determine the Phenotype based on the Genotype from page 1 For example: if you flipped two RR for face shape, the phenotype would

be Round After all of the Phenotypes are determined, draw your baby by using the

traits from the Phenotype chartObjectives for Class:• Experiment with probability to see the diversity of offspring that can be made through sexual

reproduction

Bio 9C: Wednesday, 3.24.10Title: Genetic Inheritance and Variation

Homework: Complete the monohybrid worksheet practice problems

Do Now: Learning how to use the “CLICKERS” On the next slide…

Today’s Objectives: Differentiate between genotypes and phenotypes Experiment with probability to see the diversity of offspring

that can be made through sexual reproduction 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: • Differentiate between genotypes and

phenotypes• Experiment with probability to see the

diversity of offspring that can be made through sexual reproduction

Wednesday, 3.24.10: Block 1

Learning how to use the “Clickers”

What are they? Audience response tools that allow you

to enter your response/ answer by “clicking” the handheld response card (sort of like Jeopardy).

Why are they cool? Everyone can participate in class! You can answer questions from class

without waiting to be called upon! In seconds, we can determine how many

people really understand what we are doing and adjust accordingly to meet the needs of the class!

Learning how to use the “Clickers”

How do they work? Each of you will get a clicker

assigned to you (based on your last name position in the alphabet).

Every day you come to class, you will take your Clicker from the Clicker rack and sit down.

As I post slides that have questions for you to answer, you will “click” your answer on the handheld Clicker.

Your response goes right to the computer where software records the responses, tabulates the numbers of responses, and creates graphs to show how the class responds.

Your Clicker Number:Write it on the FRONT of your notebook

Clicker Number

Student Name

1 Beverly2 Alain3 Alejandra4 Drishti5 Derrell6 Michael7 Carl8 Arielle9 Rowan10 Nehemie11 Maddie12 Aaliyah

Clicker Number

Student Name

13 Yasmine14 Jasmine15 Erik16 Kiraleah17 Gustavo18 Ashley19 Milly20 Martin 21 Rishab22 Larissa23 Hannah

Now… Get your clicker Once everyone has their clicker…

Hold down the Channel button for a few seconds

Press ZERO and then TWO Press Channel again

(This will set your clicker to the proper channel)

DO NOW: Does this picture show GENOTYPES or PHENOTYPES? “Click” your answer…

A. B.

83%

17%

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 phenotype?

What is the genotype?


Now we will use the Clickers to collect the Class Results for question 4.

To do this, enter in your baby’s phenotype for each of the following traits:

Face Shape Cleft Chin Widow’s Peak Earlobes Gender

As we address each trait, write the percentages for each phenotype in the Class Results chart.

Use this data to complete analysis question #4.

“Makin’ Babies”: Review and Analysis (w/ the Clickers)


reproduction

Phenotype Class Results:What is the face shape of your baby?

1 2

17%

83%1. Round (dominant)

2. Square (recessive)


reproduction

1 2

26%

74%

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?

1 2

43%

57%1. Yes, it’s present

(dominant)2. No, it’s absent

(recessive)


reproduction

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

1 2

22%

78%1. Unattached (dominant)

2. Attached (recessive)


reproduction

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

1 2

52%

48%

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


reproduction

Complete the Analysis Questions for the “Makin’ Babies” Activity

Please complete the remaining questions…

Genetic Inheritance & Variation - Mendel’s Principle of Segregation

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

Wednesday, 3.24.10: Block 2

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

4%9%

0%

87%1. Codominant2. Polygenic 3. Recessive4. Dominant

Vocabulary Review 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

48%

52%1. Process A2. Process B

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?




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

Mendel’s Discoveries Principle of Segregation Principle of Independent

Assortment



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

Principle of Segregation (continued…)

This explains why the recessive trait reappears in the F2 generation…

In ¼ of the offspring.

Source of Gametes

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%

Bio 9C: Thursday, 3.23.10Title: Genetic Inheritance & Variation – “Counting Corn” Day 1

Homework: Complete the calculations for the Part B and C analysis.

Complete conclusion questions 1 and 2. (note: different than assignment sheet). Due Monday

Do Now: Homework Review: We need 3 volunteers to put problems 2,

3, and 4 on the side board Everyone else is “clicking” their answers in

Today’s Objectives: Use Punnett Squares to solve monohybrid crosses Use Punnett Squares to solve dihybrid crosses Use Mendel’s Principle of Independent Assortment to explain how genetic

variation is created in individuals.

Question 2 (d): What is the probability of purple flowers?

1 2 3 4

15%

0%

75%

10%

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

13%

0%0%

87%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

83%

4%0%

13%

1. 25%2. 50%3. 75%4. 0%

Review: Principle of Segregation and Meiosis

AA

AaAaAaAa

A aA a

aaDiploid Cells

Segregation

Fertilization

Possible Haploid

Gametes

Possible Diploid Zygotes

Part A: Developing Your Hypothesis Use your knowledge of probability and inheritance to develop a

hypothesis for the percentages of two different phenotypes found in the F2 generation of corn offspring (seeds).

Part B: Investigating an actual F2 Test your hypothesis with an ear of corn. The kernels on these ears

of corn are the F2 offspring from a cross that began with two parental varieties of corn with contrasting phenotypes (one yellow one purple).

Part C: Investigating Two Traits For this section you will see what happens when you look at the

inheritance of two separate traits? Mendel studied this by looking at seed color AND seed shape in pea plants – and that’s what you will do next, with an ear of corn.

“Counting Corn”: Genetic Crosses in Organisms

Objectives for Class:• Use Punnett Squares to solve monohybrid crosses• Use Punnett Squares to solve dihybrid crosses• Use Mendel’s Principle of Independent Assortment to explain how genetic variation is

created in individuals.


Part A Procedure: Examine the pictures for corn kernel color and answer questions in your notebooks Parent

(P1)

First Generation (F1)

Second Generation (F2)

Parent (P2)

X

X

Bio 9C: Friday, 3.26.10Title: Genetic Inheritance & Variation – “Counting Corn” Day 2

Homework: Complete the calculations for the Part B and C analysis.

Complete conclusion questions 1 and 2. (note: different than assignment sheet). Due Monday

Do Now: Get an ear of corn and begin counting the kernels for

Part B

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.

Part B: Investigating an actual F2 Test your hypothesis with an ear of corn. The kernels on these ears of corn are the

F2 offspring from a cross that began with two parental varieties of corn with contrasting phenotypes (one yellow one purple).


Phenotype Your Group’s Counts Class Count Totals

Yellow

Total Kernels ____________

Purple

Total Kernels ____________

Total # of Kernels Counted

Bio 9C: Monday, 3.29.10Title: Genetic Inheritance & Variation – Mendel’s Principle of Independent Assortment

Homework: Brainstorm the background information in your notebook

(clearly label this!). Type the background information section based on your brainstorm (don’t forget to make connections between the points).

Completed typed lab reports are Due Thursday!

Do Now: On the next slide…

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.

Answering Corn Lab Questions Why Part A? How does Part A connect to Part B? How does having 2 traits change things?

Bio 9C: Tuesday, 3.31.10Title: Genetic Inheritance & Variation - Mendel’s Principle of Independent Assortment

Homework: Finish the Dihybrid Crosses Worksheet if you didn’t finish it in

class. Revise or complete Steps 5-9 of Part C on the Corn Lab if you

haven’t already, or if you can do a better job after today’s lesson on dihybrid crosses. Refer to the Dihybrid Crosses Worksheet for help if you need it.


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.

DO NOW: In sheep, the allele for white wool is dominant (W) and the allele for black wool (w) is recessive. A farmer has mated two sheep for a few years and produced six offspring : 4 white and 2 black. One of the sheep has black wool and the other has white wool. Which of the following is likely the genotypes of the parent sheep?

1 2 3 4

55%

20%

10%15%

1. WW and Ww2. WW and ww3. Ww and Ww4. Ww and ww

Quick Review from Monday 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 1Cell 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 segregate 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


example: dihybrid cross

Example: Dihybrid Cross(only write what’s in purple)

Unattached earlobe (E) is dominant over attached (e)

Black hair (B) is dominant over blond hair (b) What are the potential phenotypic

combinations?

Two parents are heterozygous for both traits:(1) Write the parent genotypes:

(2) What gametes can they make?

Example: Dihybrid Cross continued(3) Write the gametes along the sides of a

BIG Punnett Square (4 boxes x 4 boxes = 16 boxes)

(4) Use the Punnett Square to calculate probabilities!

What is the probability of having a baby with attached earlobes and black hair?

1 2 3 4

0% 0%

86%

14%

1. 1/162. 8/163. 3/164. 12/16

Remainder of Class: Collect and Review Class Data Setting up our Dihybrid cross for Part C of the

corn lab/ finishing Part C Begin Dihybrid cross activity




Bio 9C: Thursday, 4.1.10Title: Genetic Inheritance & Variation - Mendel’s Principle of Independent Assortment

Homework: Complete the Mendelian Genetics Review packet

Do Now: Very Quickly on the next slide…

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.

Q3 from HW: What is the probability that Charlie and Jennifer’s child will have a flat chin and bent pinkies?

1 2 3 4

0% 0%0%

100%1. 50%2. 25%3. 75%4. 0%




Today in Class: Collect and Review Class Data Setting up our Dihybrid cross for Part C of the

corn lab/ Finishing Part C Begin Mendelian Genetics Review Activity

Table 1: Part C Class DataGroup % Yellow Corn % Purple Corn

1

2

3

4

5

6

7

8

9

10

11

12




Remainder of Class: Setting up our Dihybrid cross for Part C of the corn

lab/ Finishing Part C Begin Mendelian Genetics Review Activity

Bio 9C: Monday, 4.5.10Title: Big Quiz Review Day – Genetics and Inheritance

Homework: Labs are Due Wednesday at the start of class Study for the BIG Quiz on Friday


Today’s Objectives: Review Genetics Content for Wednesday’s BIG QUIZ

(small test)

Do Now: Data Analysis Practice

Take out a calculator. Calculate the % of offspring with long wings. Show your work! Calculate the % of offspring with vestigial wings. Show your

work! Do you think vestigial wings are dominant, recessive, or co-

dominant? Why? What are the genotypes of the two long-winged fruit flies that were

crossed (mated) in this example?

Do Now: Analyzing Genetic Data % of Long Wings =

73 divided by 95 = 0.768 = 77% Long Wings % of Vestigial Wings =

22 divided by 95 = 0.2316 = 23% Vestigial Wings

Vestigial Wings are…Recessive because two parents with long wings had some babies with vestigial wings. This means the parents carried a copy of the vestigial allele but didn’t show it.

The two long-winged fruit fly parents are…Heterozygous (Aa x Aa)

What percent of the wings would you expect to be long?

1 2 3 4

0% 0%

100%

0%

1. 25%2. 50%3. 75%4. 100%

Why are the actual percents a bit different?

Have you completed the Mendelian Genetics Review Packet?

1 2

50%50%1. Yes2. No

Do you feel like you confidently answered the “challenge” questions in Part III of the Review Packet?

1 2 3

55%

0%

45%

1. Yes2. Somewhat3. No

Big Quiz Review: Mendelian Genetics

Continue with the Mendelian Genetics Review Packet.

If you feel like you have confidently answered all of the questions, then complete an “extension” packet

bio 9c: thursday, 3.17.11 title: introduction to genetic inheritance and variation

Documents

diversity of offspring

genetic diversity

mendelian genetics probability

dominant allele

particular trait

sexual reproduction

present mendelian genetics

end of class