Name _____________ ________ Class___________ *GENETIC NOTES & WORKSHEETS

DAY 1: Mendelian Genetics Vocabulary

A. Genetics- Study of

B. Heredity- The passing on of characteristics (traits) from _______________ to

____________________

C. Trait – A particular that can vary from one individual to another.

Ex: ________

D. Fertilization- Joining of male and female (reproductive cells)

during ___________reproduction

E. Genes- Section of a chromosome that determine the trait we will inherit Ex: Sally

has the gene for brown hair

F. Alleles- of one gene

Ex: Brown, red, or blond hair are all different forms the hair color gene

G. Dominant Gene- expressed if present for a trait

Dominant allele = capital letter (B)

H. Recessive Gene- Only expressed if __________ are present for

that trait

Recessive allele = lowercase letter (b)

PRACTICE! Use the term Dominant or Recessive to identify the type of trait shown.

1. TT

2. tt

3. Tt

4. SS

5. ss

6. Ss

I. Homozygous- Organisms have alleles for a trait

Ex: RR (BIG/BIG) or rr (small/small)

J. Heterozygous- Organisms have alleles for a trait

EX: Rr (BIG/small)

PRACTICE! Use the term Homozygous or Heterozygous to identify each of the following:

1. AA

2. Aa

3. Mm

4. gg

5. GG

6. Gg

K. Genotype- the genetic makeup (________) or combination of _______

___________________ (one from mom and one from dad)

Ex: QQ, Qq, qq

L. Phenotype- characteristics of the trait

Ex: Brown Hair (what you see)

Gregor Mendel (1822-1884)

A. Austrian Monk

B. The “ ________________”

C. Cross Bread common _______ to study

the inheritance of traits through each generation.

Mendel’s Pea Plant Experiment

A. P1 –

B. F1-

C. F2-

EGG

SPERM

PAP

3. Punnett Square

Punnett Squares following Mendelian Rules of Genetics

A. A Punnett Square is a __________________ used to _________________ the outcome of a

particular cross or breeding experiment

B. Used to determine the __________________________of _____________offspring’s

genotypes and phenotypes

C. This does ___________determine how many offspring will be produced or exactly what the

offspring’s genotype and phenotype will be…just the chances!

D. There are five steps (you must always show your work)

1. Key- List the trait, Both alleles, and which phenotype corresponds with each

allele

2. Parents- List the genotypes of each parent

3. Draw the Punnett square

4. Determine the genotype ratio

5. Determine the phenotype ratio

Complete the following Punnett squares using all 5 steps SAMPLE PROBLEM: Wavy hair is dominant to straight hair. Cross two heterozygous parents.

1. Key:

2. Parents: ____X_____

4. Genotype:

5. Phenotype:

Worksheet Problems: YES, THIS IS FOR A GRADE. YOU need to complete it!

For each phenotype below, list the POSSIBLE genotypes (remember to use the letter of the dominant trait)

Brown eyes are dominant to blue eyes Widow’s peak is dominant to straight hair line

________Homozygous Brown ________Widow’s peak

________Heterozygous Brown ________Widow’s peak

________blue ________straight hair line

Mendel’s Conclusions:

A. Biological Inheritance is ________________ from one

________________________ to the next.

Ex: your traits were determined by your

parents’ genes that were passed onto you.

B. Law of

During _____________, the pairs of _________

__________________ so that each gamete receives

only one gene for each trait

C. Law or Principal of

Some alleles are _________________ and some are

______________________.

Recessive traits will only show up if dominant is

___________ present

PAP

1. In rabbits, black hair color is dominant to white. Cross homozygous black rabbit with a white rabbit.

1. Key:

2. Parents: _______X_______

4. Genotype:

5. Phenotype:

2. In roses, red is dominant to yellow. Cross a homozygous red rose with a heterozygous red rose

1. Key:

2. Parents: ________X_______

4. Genotype:

5. Phenotype:

3. In cats, long tails are dominant to short tails. Cross two heterozygous long tail cats.

1. Key:

2. Parents: ________X_______

4. Genotype:

5: Phenotype:

4. In lizards, green skin color is dominant to purple. Cross a heterozygous green lizard with a purple lizard.

1. Key

2. Parents:

4: Genotype Ratio

5: Phenotype Ratio

Match the terms with the definitions.

1. _____ Genetics A. the weaker of a pair of genes

2. _____ Dominant B. When the pair of genes are identical

3. _____ Genes C. the study of heredity

4. _____ Homozygous D. The passing of traits from parents to their young

5. _____ Gamete E. the stronger of a pair of genes

6. _____ Recessive F. sex cells, wither male or female

7. _____ Heterozygous G. segment of DNA that codes for a particular protein

8. _____ Heredity H. the physical appearance of an organism

9. _____ Phenotype I. the actual genetic make-up of an organism

10. _____ Genotype J. when the pair of genes are different

1. In humans, a widow’s peak is dominant to a straight hair line. Cross homozygous widow’s peak with a

straight hair line.

1. Key:

2. Parents: _______X_______

4. Genotype:

5. Phenotype:

2. In humans, a widow’s peak is dominant to a straight hair line. Cross a straight hair line with a straight hair

line.

1. Key:

2. Parents: _______X_______

4. Genotype:

5. Phenotype:

3. Mendel discovered that yellow pea color is dominant to green pea color. Cross a green pea plant with a

heterozygous yellow pea plant.

1. Key:

2. Parents: _______X_______

4. Genotype:

5. Phenotype:

4. Using Mendel’s information about pea plants, (yellow is dominant to green) cross a homozygous yellow

pea plant with a heterozygous yellow pea plant.

1. Key:

2. Parents: _______X_______

4. Genotype:

5. Phenotype:

PAP

DAY 1

Fur Color: Coat Texture: B: Black R: Rough b: White r: Smooth

Mendelian Genetics- Dihybrid Crosses (Crossing 2 Traits/Factors)

Review of Monohybrid Crosses

Remember, monohybrid crosses involve only ____________ trait

Example: In fruit flies, red eyes are dominant over white eyes. RR x rr

In this example you are only examining the ______ ______________ trait.

Dihybrid Cross: the study of ________ pairs of contrasting traits at the same time

Example: Fur color WITH Coat Texture

Mother is black fur AND rough coat Father is black fur AND rough coat BbRr BbRr Notice that each parent has _____ ________so that results in _____ ________ (1 trait= 2 alleles)

The Law of Independent Assortment

During ____________formation, segregating pairs of unit ____________ (alleles) assort

__________________ of each other when on different chromosomes.

The two traits are inherited totally independently of each other.

Example: Fur color is inherited independently of coat texture.

Sample problem 1: We will cross a heterozygous individual with another heterozygous individual. Their

genotypes will be BbRr x BbRr

Step 1: Find ALL possible gametes that can be made from each parent. Remember, each gamete must have one B and one R. USE THE FOIL METHOD

B b R r x B b R r

Step 2: Arrange all possible gametes for one parent on the top of your Punnett Square and the other parent on the side

Step 4: Figure out the genotypic and phenotypic ratios:

Fur Color: B: Black b: White

Coat Texture: R: Rough r: Smooth

Step 3: Fill in the Punnett Square

(find the possible genotypes of the offspring)

How many of the offspring would have a black, rough coat? _____

How many of the offspring would have a black, smooth coat? _____

How many of the offspring would have a white, rough coat? _____

How many of the offspring would have a white, smooth coat? _____

Phenotypic ratio _____:_____:_____:_____

Sample Problem 2: What are the genotypic and phenotypic ratios in the offspring resulting from a cross between two people heterozygous for eye color and eyelash length? What is the phenotype of the parents in this cross? B – Brown L - Long

b – Blue l – short

Parents are heterozygous for both traits. The cross is B b L l x B b L l.

STEP 1: Determine the possible gametes that the parents can produce. USE FOIL for independent assortment STEP 2: Enter the possible gametes at the top and side of the Punnett square. Always keep the same letter first and capitals of each first. STEP 3: Complete the Punnett square by writing the alleles from the gametes in the appropriate boxes. The alleles from the gamete above the box and the alleles from the gamete to the side of the box are combined inside each of the boxes. The letters inside each box represent the probably genotypes of the offspring resulting from the cross.

STEP 4: Determine the genotypes of the offspring. Count each row from left to right (as you read). Mark each one as it is used.

Determine the phenotypes of the offspring. Count each row vertically (top to bottom).

Genotypes Phenotypes

Practice Problems: In mice, the ability to run normally is a dominant trait. Mice with this trait are called running mice (R). The recessive trait causes mice to run in circles only. Mice with the trait are called waltzing mice (r). Hair color is also inherited in mice. Black hair (B) is dominant over brown hair (b). For each of the following problems, draw a Punnett Square in the space provided and fill in the information on the indicated lines. 1. Cross a heterozygous running, heterozygous black mouse with a homozygous running, homozygous black

mouse. Parents: _________X__________ 2. Cross a homozygous running, homozygous black mouse with a heterozygous running, brown mouse.

Parents: _________X__________

3. Cross a waltzing, brown mouse with a waltzing, brown mouse. Parents: _________X__________ 4. Cross a homozygous running, heterozygous black mouse with a waltzing brown mouse.

Parents: _________X__________

CREATE THE KEY:

5. Cross a heterozygous running, brown mouse with a heterozygous running, homozygous black mouse. Parents: _________X__________ 6. Cross a hemophilic man with blood type AB with a hemophilic-carrier woman with

blood type A (homozygous).

Parents: _________X__________

7. A colorblind man with type B blood, whose dad was type O marries a normal woman with no colorblindness in her family and has type AB blood. What are the possible ratios for future children?

Parents: _________X__________

8. A woman whose dad has Duchenne’s muscular dystrophy and type AB blood marries a man that is normal with type AB. What are the possible outcomes for their future family?

Parents: _________X__________

Name:______________________________________Date_______________Period___________PAP

Non-Mendelian Incomplete Dominance *Exceptions to the Mendel Rule*

Notes:

Incomplete Dominance

A. A cross between organisms with phenotypes

Ex: Red x White

B. Produce offspring with a phenotype that is a

____________________ of the parental traits Ex: Pink is a blend of red & white

C. EXAMPLE: If a homozygous flowered snap dragon plant (RR) is

crossed with a homozygous flowered snap dragon plant (WW), all of

the F1 offspring will have flowers.

1. RED flower x WHITE flower PINK flower

*be careful- notice that the alleles are ALL capitalized

D. The of individuals is

(in the middle) between those of two homozygotes

Sample Problem:

In another flower, if red (RR) and blue (BB) flowers are crossed, they produce a 3rd purple (RB) flower

What would be the genotype ratio and phenotype ratio if you crossed two purple flowers?

Cross of two purple flowers (parents) _______ X _______

What are gamete possibilities?

genotype ratio ________________________

phenotype ratio _______________________

Can you have a heterozygous red or hybrid blue flower? _______

Section 1: Incomplete dominance in four-o’clocks - When a four-o’clock plant homozygous for red flowers is

crossed with one homozygous for white flowers, all of the offspring bear pink flowers. Cross a homozygous red

flowered plant with a homozygous white flower plant.

1. Key:

2. Parents:

4. Genotype:

5. Phenotype:

What is the genotype of the F2 generation from the problem above?

1. Key:

2. Parents:

4. Genotype:

5. Phenotype:

Explain how the red or white variety of four-o’clocks is maintained:

___

Section 2: Inheritance of color in MInk – The same principle of inheritance of coat color in Shorthorns also

applies to mink. When a mink homozygous for white fur is crossed with one homozygous for black fur, the

offspring are all Koh-i-nur or shiny black cross. Show the result in crossing two Koh-i-nur minks. Show your work.

1. Key:

2. Parents:

4. Genotype:

5. Phenotype:

Explain how people who raise mink could maintain only minks with white fur:

Section 3: Practice Incomplete Dominance – show all work.

1. In noses, dry nostrils are incompletely dominant to runny nostrils. A cross will result in a slimy nostril.

a. Cross a slimy nostril with a dry nostril.

Key:

Parents:

Genotype:

Phenotype:

b. Cross a dry nostril with a runny nostril.

Key:

Parents:

Genotype:

Phenotype:

c. Cross two slimy nostrils.

Key:

Parents:

Genotype:

Phenotype:

2. In people, happy people are incompletely dominant to sad people. A cross between the happy and sad people

results in a grumpy person. Cross two grumpy people.

Key:

Parents:

Genotype:

Phenotype:

PAP

Name___________________________________________Date_______________Period______ PAP

Non-Mendelian Genetics: Codominant Traits with Blood Typing

Codominance

A. A cross between organisms with _ phenotypes

1. Ex: Red x White

B. Produce offspring with a phenotype that

displays traits at the same time

1. Ex: Red and White striped

C. EXAMPLE: If a homozygous flowered snap dragon plant (RR) is crossed with a

homozygous flowered snap dragon plant (WW), all of the F1 offspring will have

flowers.

1. RED flower x WHITE flower RED AND WHITE flower

Human Codominance

A. Sickle-Cell Anemia

1. An individual who is heterozygous for sickle-cell alleles will express BOTH _________

and blood cells.

The oxygen carrying protein hemoglobin differs by one amino acid than the regular cause

the shape to change: Normal RBC are and abnormal

are or sickle shaped.

2. Abnormally shaped blood cells ,

______________, and result in tissue damage and .

3. Heterozygous individuals are said to have the sickle-cell trait because they show signs of sickle-cell

related disorders if the availability of oxygen is reduced.

B. Blood types

1. Blood type is determined by alleles. This

means there are more than two types of alleles possible that can make up a paring.

_______ : red blood cells produce A antigens (protein)

on the outside of the cell

A. Allele is expressed IA because it is _______

_______ : red blood cells produce B antigens (protein)

on the outside of the cell

B. Allele is expressed IB because it is _________

_______ : red blood cells will produce an antigen (protein)

C. Allele is expressed i because it is

2. Determining Blood types is necessary before you receive a blood transfusion because incompatible

red blood cells together or clot causing death.

3. Your immune system or antibodies recognizes the red blood cells belonging to you. If cells with a

_____ ____________ of antigen enter your body your immune system will attack them.

PAP

Complete the following chart:

Phenotype or blood type All genotypes possible

Type A

Type B

Type AB (Codominant)

Type O (recessive)

***The true universal blood donor are O- ***The true universal recipient is AB+

SAMPLE PROBLEMS:

Cross a parent with Type AB blood with a parent that has heterozygous type A blood.

Parents: ___________X_____________

Genotype:

Phenotype:

Cross a heterozygous type A blood father with a heterozygous type B blood mother.

Parents: ___________X_____________

Genotype:

Phenotype:

Practice Problems: Include all steps.

1. Is it possible for parents with type A blood to have a child with type O blood? __________

Show your work and PROVE your answer.

A. If it is possible, list the necessary genotypes of the parents and explain why their child could have a

different blood type.

B. What is the genotype of a child with type O blood? ___________

C. Work the following cross: Heterozygous type A x heterozygous type B

Parents: ___________X_____________

Genotype:

Phenotype:

PAP

2. A man with homozygous A blood has children with a woman with heterozygous B blood. What are the

possible blood types for their children?

Parents: ___________X_____________

Genotype:

Phenotype:

3. Pick one child from problem #2 and cross that person with a person with heterozygous A blood.

Parents: ___________X_____________

Genotype:

Phenotype:

4. Suppose that a man with type A blood marries a young woman who has type AB blood. What blood types

would you expect to find among their children. Remember to take all possibilities into account.

5. Mr. Jones was taken to court and charged with being the father of a woman’s child. He is homozygous

type A blood. She is heterozygous type B blood. The child is type O blood. Is Mr. Jones the father? Show

all your work.

6. Two newborn babies were accidentally switched in a hospital. In an effort to correct the mistake blood

types of the babies and parents were determined. Here are the results of the blood types. Which baby

belongs to which parent?

Baby 1 – type O Mrs. Brown – type B Mrs. Smith – type B

Baby 2 – type B Mr. Brown – type AB Mr. Smith – type B

A. Baby 1 belongs to the parents ________________________. Prove your answer with 4 steps.

B. Baby 2 belongs to the parents ________________________. Prove your answer with 4 steps.

PAP

Non- Mendelian Genetics: SEX- LINKED TRAITS

A. Determining Sex

1. Humans have a number of

chromosomes or

2. 22 of the pairs are autosomes, they are the for

males and females

3. The 23rd pair of chromosomes in males

and females

These are the sex chromosomes and are

indicated by ___ and

determine the baby’s sex.

B. Inheriting Sex linked traits

1. Genes located on the _________

___________________ are called sex- linked traits

2. Because the Y chromosome is small it carries

, including the male determinant sex gene.

3. Males who receive a on the X

chromosomes will express the_______________

_________ because he cannot inherit on

the Y chromosome.

There is dominant allele to the recessive gene

4. have a higher percent chance of expressing the recessive trait

C. Examples in Humans

1. Hemophilia

Causes a problem with

Caused by a ___________________ allele on the _______ chromosomes

Males: 1/10,000

Need __________ recessive allele from carrier mom

Females: 1/10,000,000

Need _________ recessive alleles; one from mom and one from dad

Sex- Linked Traits

2. Color Blindness

People who have red-green color blindness cannot differentiate between the two colors.

Caused by a ___ allele on the X chromosomes

Sample problem 1: A colorblind man marries a woman who is not colorblind. Assuming there is no colorblindness in the woman’s ancestry, what will most likely be the genotype and phenotypes of their sons and daughters? Show your work

a. Key: e. Punnett Square

b. Parents:

c. Genotype Ratio:

d. Phenotype Ratio:

USE THIS CHART TO HELP YOU ANSWER THE PRACTICE PROBLEMS THAT FOLLOW!!

*Males either have colorblindness or they don’t. They only have one X chromosome that was received from the mother. ** More males have hemophilia and color blindness because males need one gene for hemophilia or Color-blindness to occur.

PRACTICE PROBLEMS: SHOW ALL 5 STEPS!

A. A normal woman marries a normal man producing two colorblind sons, two normal sons and three normal daughters. Show your work.

1. Key: 3. Punnett Square

2. Parents:

3. Geno Ratio:

4. Pheno Ratio:

B. A female carrier of hemophilia marries a normal male. What are the genotypes and phenotypes of the possible offspring? Show your work.

1. Key: 3. Punnett Square

2. Parents:

3. Geno Ratio:

4. Pheno Ratio:

Colorblindness- C= normal c’= colorblindness

Hemophilia- H=normal h=hemophilia

PHENOTYPE GENOTYPE PHENOTYPE GENOTYPE

Female normal X X Female normal X X

Female normal, Carrier Female normal , Carrier

Female, color-blind Female, hemophiliac

Male normal X Y Male normal X Y

Male, color-blind Male hemophiliac

C. Normal man X Hemophiliac woman

1. Key: 3. Punnett Square

2. Parents:

3. Geno Ratio:

4. Pheno Ratio:

D. Hemophiliac man X Heterozygous normal woman

1. Key: 3. Punnett Square

2. Parents:

3. Geno Ratio:

4. Pheno Ratio:

E. Hemophiliac man X Homozygous normal woman 1. Key: 3. Punnett Square

2. Parents:

3. Geno Ratio:

4. Pheno Ratio:

F. If a normal woman marries a normal man and two of their three sons are hemophiliacs,

what is her genotype? Is this possible? Show this problem.

1. Key: 3. Punnett Square

2. Parents:

3. Geno Ratio:

4. Pheno Ratio: