VANDERVEERBIOLOGY

Genetic Probability

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Teachers

Students

Teacher’s Lounge

Learning Goals: Students will have a basic understanding of genetic

probability Students will be able to distinguish between a

dominant and recessive gene Students will be able to distinguish between a

genotype and phenotype

Teacher’s Lounge

Learning Objective: Students will be able to use knowledge

gained in this activity to answer genetic probability questions with 75% accuracy

Students

Procedures: Follow each instructional activity Participate in each practice activity Complete the assessment with 75% accuracy

Good day! My name is Gregor

Mendel and I will be assisting you

as you learn about genetic probability.

Home

Introduction

Monohybrid Cross

Dihybrid Cross

Multiplication Rule

Assessment

Let’s get

started!

Introduction to Genetic Probability

On the following slides you will find basic genetic definitions you need to know, or already know:

Genetic Probability Definitions

1. Allele: a form of a gene2. Dominant: will be expressed in the organisms

appearance or physiology; usually represented by an upper case letter

3. Recessive: will not be expressed in the organisms appearance or physiology unless the individual has 2 copies of the recessive allele; usually represented by a lower case letter

Genetic Probability Definitions Continued

4. Genotype: the genetic composition of an organism5. Phenotype: the observable characteristics of an

organism

Gregor Mendel Video

Oh, that’s me!

Section Review

1. What is an allele? a. A chromosome

b. A letter

c. A form of a gene

Genetic Probability Definitions

1. Allele: a form of a gene2. Dominant: will be expressed in the organisms

appearance or physiology; usually represented by an upper case letter

3. Recessive: will not be expressed in the organisms appearance or physiology unless the individual has 2 copies of the recessive allele; usually represented by a lower case letter

4. Genotype: the genetic composition of an organism

5. Phenotype: the observable characteristics of an organism Back to review

question 1

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Next question

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You can do it!

2. If a gene is not expressed in the organisms appearance it is:

a. Dominant

b. Recessive

c. An allele

Genetic Probability Definitions

1. Allele: a form of a gene2. Dominant: will be expressed in the organisms

appearance or physiology; usually represented by an upper case letter

3. Recessive: will not be expressed in the organisms appearance or physiology unless the individual has 2 copies of the recessive allele; usually represented by a lower case letter

4. Genotype: the genetic composition of an organism

5. Phenotype: the observable characteristics of an organism Back to review

question 2

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3. The genetic composition of an organism is its ____________ and the observable characteristics of an organism is its ____________. a. Phenotype; genotype

b. Genotype; phenotype

c. Genotype; genotype

Genetic Probability Definitions

1. Allele: a form of a gene2. Dominant: will be expressed in the organisms

appearance or physiology; usually represented by an upper case letter

3. Recessive: will not be expressed in the organisms appearance or physiology unless the individual has 2 copies of the recessive allele; usually represented by a lower case letter

4. Genotype: the genetic composition of an organism

5. Phenotype: the observable characteristics of an organism Back to review

question 3

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Monohybrid Cross

Up Next:

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Monohybrid Cross

A monohybrid cross is a cross involving a single trait with two alleles.

In example, X is the trait and X, x are the alleles.

X X

x Xx Xx

x Xx Xx

Monohybrid Cross Using a Punnett Square

Seed color: Y=yellowy= green

Cross: Yy x YY

Y y

Y

Y

Y y

Y YY Yy

Y YY Yy

Step 1: Click here Step 2:

Click here

What is the genotypic ratio? 2 YY: 2 Yy or 1 YY: 1YyWhat is the phenotypic ratio? All yellow

Y y

Y YY Yy

Y YY Yy

Monohybrid Cross Using a Punnett Square: Practice

Eye color: B=brownb= blue

Cross: Bb x Bb

B b

B

b

B b

B BB Bb

b Bb bb

Step 1: Click here Step 2:

Click here

Check your work:

What is the genotypic ratio? 1 BB: 2 Bb: 1 bbWhat is the phenotypic ratio? 3 brown: 1 blue

B b

B BB Bb

b Bb bb

Dihybrid cross

A dihybrid cross is a cross involving 2 traits with two alleles each.

In example, X and Y are the traits and X, x/ Y, y are the alleles.

XY XY XY XYxy XxYy XxYy XxYy XxYyxy XxYy XxYy XxYy XxYyxy XxYy XxYy XxYy XxYyxy XxYy XxYy XxYy XxYy

Dihybrid Cross Using a Punnett Square

Seed color: Y=yellowy= green

W= Wrinkledw=round

Cross: YyWw x YywwYW Yw yW yw

Yw

Yw

yw

yw

YW Yw yW yw

Yw YYWw YYww YyWw Yyww

Yw YYWw YYww YyWw Yyww

yw YyWw Yyww yyWw yyww

yw YyWw Yyww yyWw yyww

Step 2: Click here

Step 1: Click here

What is the genotypic ratio? 2 YYWw: 2 YYww: 4 YyWw: 4 Yyww: 2 yyWw: 2 yyww reduced to 1 YYWw: 1 YYww: 2 YyWw: 2 Yyww: 1 yyWw: 1 yyww

What is the phenotypic ratio? 6 Yellow wrinkled: 6 Yellow round: 2 green wrinkled: 2 green round Reduced to 3 yellow wrinkled: 3 yellow round: 1 green wrinkled: 1 green round

YW Yw yW yw

Yw YYWw YYww YyWw Yyww

Yw YYWw YYww YyWw Yyww

yw YyWw Yyww yyWw yyww

yw YyWw Yyww yyWw yyww

Dihybrid Cross Using a Punnett Square: Practice

Seed color: B=Brownb= blue

G= brunette g= blonde

Cross: BBGg x bbggBG Bg BG Bg

bg

bg

bg

bg

BG Bg BG Bg

bg BbGg Bbgg BbGg Bbgg

bg BbGg Bbgg BbGg Bbgg

bg BbGg Bbgg BbGg Bbgg

bg BbGg Bbgg BbGg Bbgg

Step 1: Click here Step 2:

Click here

Check Your Work:

What is the genotypic ratio? What is the phenotypic ratio?

BG Bg BG Bg

bg BbGg Bbgg BbGg Bbgg

bg BbGg Bbgg BbGg Bbgg

bg BbGg Bbgg BbGg Bbgg

bg BbGg Bbgg BbGg Bbgg

Check Your Work:

What is the genotypic ratio? 8 BbGg: 8 BbggReduced to 1 BbGg: 1 Bbgg

What is the phenotypic ratio? 8 Brown/brown: 8 Brown/ blondeReduced to 1 Brown/brown: 1 Brown/blonde

Multiplication Rule

If two events are independent, then the joint probability is:

P(A and B)= P(A) x P(B)

Dihybrid Cross using Multiplication Rule

Seed color: Y=yellowy= green

W= Wrinkledw=round

Cross: YyWw x YyWwWhat is the probability of getting the genotype YyWw?(2/4) (2/4)= 4/16= ¼ What is the probability of getting the genotype YYww?(1/4)(1/4)= 1/16

Dihybrid Cross using Multiplication Rule: Practice

Seed color: B=Brownb= blue

G= brunette g= blonde

Cross: bbGg x bbGGWhat is the probability of getting the genotype bbGg?What is the probability of getting the genotype bbGG?

Check Your Work:

What is the probability of getting the genotype bbGg?

(1)(1/2)= ½ What is the probability of getting the genotype

bbGG?(1)(1/2)= ½

Assessment

You must answer ¾ of the following questions correctly to complete this activity.

This will be a piece of cake

now that we’ve

completed the activities!

Question 1

An allele is: a. A form of a gene

b. Gregor Mendel’s nickname

c. A chromosome

You’re right!

Next Question

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Question 2

Solve using a Punnett Square. What is the phenotypic ratio of the following cross?

Bb x BB

c. All are the same

a. 1:1

b. 2:2

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Next Question

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Ponder this one

some more

Question 3

Solve using a Punnett Square. What is the genotypic ratio of this cross?

YyWw x YyWwa. 1:1:2:2:1:1

b. 9:3:3:1

c. 12:3:1

You’re right!

Next Question

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Question 4

Solve using the Multiplication Rule. What is the genotypic ratio of the following cross?

Yyww x yyww

a. 1:1

b. 2:2

c. 9:3:3:1

You’re right!

Final Slide

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Almost there ...

If you have … Followed each instructional activity Participated in each practice activity Completed the assessment with 75% accuracy

Then you’re done!

Congratulations!