11.2 Applying Mendel’s Principles

11.2 APPLYING MENDEL’S PRINCIPLES

January 10, 2014

Plan for Jan. 10 Check up #1: Mendel’s Genetics

Notes: Dihybrid Cross; independent assortment

Analyzing Inheritance Activity

Do: You may refer to your class notes only.

Put: Write your answers in the space provided.

Finish By: You have 10 minutes.

When Done: Turn your paper in. Work silently on something of your choosing.

Check Up #1

How do alleles segregate when there is more than one gene?

Segregation with One Trait Does the segregation of one pair of alleles affect another pair?

Mendel followed two different genes as they passed from one generation to the next.

Dihybrid Cross• I can construct, complete, and

interpret a Punnett square to predict traits for a dihybrid cross.

Make a Punnett Square--Dihybrid Cross--

Heterozygous for size AND Heterozygous for pod color• Green dominant allele• Yellow recessive allele

• Tall dominant allele• Short recessive allele

TtGg TtGg

1. Start with the parents.


Step 2: Determine which alleles would be found in all possible gametes each parent would produce:

TtGg

T

T

t

t

TG

Tg

tG

tg

TtGg

G

g

G

g

The alleles segregate during gamete formation. Each gamete has one allele for size and one for pod color.


Step 3: Line up the genotypes in a 4 x 4 grid:

TG tG Tg tg

TG

tG

Tg

tg


Step 4: write out the new genotypes:

TG tG Tg tg

TG TTGG TtGG TTGg TtGg

tG TtGG ttGG TtGg ttGg

Tg TTGg TtGg TTgg Ttgg

tg TtGg ttGg Ttgg ttgg


Step 5: Figure out the results:TG tG Tg tg





The square color represents pod color. Alleles written in red indicate tall plants and alleles written in black indicate short plants.


What percent of offspring will be tall with green pods?:

TG tG Tg tg





9 tall/green 3 tall/yellow 3 short/green 1 short/yellow16 offspring

The Punnett square predicts that 56% (9/16x100) of offspring will be tall with green pods.

l Period 4 Biology1 D’Metries Allen Isaiah H. Rashal R. Luis Z.

2 Lillian C. Hannah E. Alia Mahuna Julian Santizo

3 Kevin O. Jun Del Rio Shakti Ojha Nick F.

4 Chloe W. Tommy W. Katharyn M. Tatiana

Eduardo T.L.

5 Joel T. Michael A Malia Austin B.

6 Junwoo Park Ram S. Jae Song Kym P.

7 Rahja A. Biying Liu Bailee R. Courtney A.

8 Priscilla R. Itzel C.A. Rozita K. Kyrie

9 Alexandra H. Andrew W. Jaime H. Haya R.

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• Collaborative Group Assignments

# Period 6 Biology1 Kayla Snapp Esmerelda P. Cheney S. Kharm H.

2 Michelle Sosnina Corallis C. Istanbul A. Noah J.

3 Kelly M. Mariah F. Selena R. Gloria P.

4 Andrea B. Julia B. Hailey N. Emily B.

5 Winston T. Eric K. Steve K. Jacob S.

6 Faisal Nhi N Soponna C Richilley

7 Ben G. Jacob B. Oscar G.

8 Olivia H. Hannah G. Abigail S. Randy C.

9 Asa C. Curtis C. Jerry Tsai Gabe H.

10 Aedan S. Chris G. Jacob N.

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• Collaborative Group Assignments

ManagerEnsures group starts quickly and stays focused; Time manager; determines which team members will read activity; ensures ALL members get a chance to respond;

SpokespersonSpeaks for the group; communicates with teacher or spokesperson of another group; Ensures ALL members agree upon questions to ask when help is needed; presents to the class if requested;

TechnicianResponsible for lab supplies; ensures group uses supplies appropriately; verifies group responses are written down, are high quality, and reflect group consensus;

AnalystPerforms math and calculations for the group; Observes and comments on group’s performance; Completes analyst’s report if requested;

Do: Working in collaborative pairs/triads you will complete the probability activity.

Put: Each student completes their own paper but uses the same data.

Finish By: You have 20 minutes.

When Done: Get your paper stamped and file it in your notebook.

Genetic Probability Activity

Plan for Jan. 14 Review Check-up #1

Discuss “Analyzing Inheritance Activity” and Genetics Probability

Wrap-up Mendel’s Genetics

Ups and Downs of Probability

RY Ry rY ry

RY RRYY RrYy RrYY RrYy

Ry RRYy RRyy RrYy Rryy

rY RrYY RrYy rrYY rrYy

ry RrYy Rryy rrYy rryy

• #2 Punnett Square for RrYy x RrYy

9 round, yellow 3 round, green 3 wrinkled, yellow 1 wrinkled, green16 offspring total

ROUNDYELLOW

wrinkledYELLOW

ROUNDGreen

Wrinkledgreen

Phenotypic Ratio 9 3 3 1

Phenotypic percentages:

9/16=

56%

3/16=

19%

3/16=

19%

1/16=

6%

#4. Is your experimental outcome the same as the predicted outcome? Explain.

#3. What is the predicted outcome of phenotypes for the cross in #2?

#5. Experiment modifications? What and why?

ROUNDYELLOW

wrinkledYELLOW

ROUNDgreen

Wrinkledgreen

Phenotypic Ratio Predicted

by Punnett Square

9 3 3 1

Phenotypic Percentages:

9/16=

56%

3/16=

19%

3/16=

19%

1/16=

6%Class Data— 50% 19% 20% 11%

• Predicted versus Experimental Phenotypes

Period 4 Class Results

ROUNDYELLOW

wrinkledYELLOW

ROUNDgreen

Wrinkledgreen

Phenotypic Ratio Predicted

by Punnett Square

9 3 3 1

Phenotypic Percentages:

9/16=

56%

3/16=

19%

3/16=

19%

1/16=

6%Class Data 57% 17% 13% 13%

• Predicted Outcomes for Phenotypes (P6):

Period 6 Class Results

Genetic Probability Probability is the likelihood that a

particular event will occur.Probability values are always between 0

and 1• Probability of 0—event never happens• Probability of 1—event always happens

Example: probability of flipping a coin and getting tails is ½ or 50%

Genetic ProbabilityIf you flip a coin three times in a row, what is the probability that it will land heads up every time?

1/2

1/2

1/2

Each toss is an independent event.

Multiply probabilities:

½ x ½ x ½ = 1/8

Genetic ProbabilityIn genetics it is usually more complex. A more complex event is simply a combination of simple events.

The Two-Factor Cross: F1

Mendel crossed true-breeding plants that produced only round yellow peas with plants that produced wrinkled green peas.

Does the gene that determines seed shape affect the gene for seed color?

The Two-Factor Cross: F1– The round

yellow peas had the genotype RRYY, which is homozygous dominant.

The Two-Factor Cross: F1– The wrinkled

green peas had the genotype rryy, which is homozygous recessive.


Which alleles are dominant for each trait? How do you know?

All of the F1 offspring produced round yellow peas so we see that none of the traits from wrinkled green parent were expressed in the F1 offspring.

• Round is dominant• Yellow is dominant


• Mendel crossed F1 plants that were heterozygous dominant for round yellow peas.

Would the two dominant alleles stay always stay together, or would they segregate independently so that any combination of traits was possible?

The Two-Factor Cross: F2 He produced 556 peas.315 of the F2 seeds were

round and yellow32 seeds were wrinkled and

green—the two parental phenotypes.

209 seeds had combinations of phenotypes, and therefore combinations of alleles, that were not found in either parent.

Principle of Independent Assortment: states that genes for different traits can segregate independently during the formation of gametes.

A Summary of Mendel’s PrinciplesThe inheritance of biological characteristics is determined by individual units called genes, which are passed from parents to offspring.

A Summary of Mendel’s PrinciplesWhere two or more alleles (forms) of the gene for a single trait exist, some forms of the gene may be dominant and others may be recessive.

A Summary of Mendel’s Principles

In most sexually reproducing organisms, each adult has two copies of each gene—one from each parent. These genes segregate from each other when gametes are formed.

A Summary of Mendel’s Principles

Alleles for different genes usually segregate independently of each other.

Genetic Probability

1/6

1/6

Each throw is an exclusive event.

Add probabilities:1/6 +1/6 = 2/6 or 1/3

What is the probability of that you will roll a 1 or 2 with dice?

Genetic Probability

The events are happening at the same time.

Multiply probabilities:

1/6 +1/6 = 1/36

What is the probability of that you will roll two dice and both will come up 1 (snake eyes)?

11.2 Applying Mendel’s Principles

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