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Table of ContentsMarch 19th 7.L.2.2 Pedigree

NotesMarch 19th 7.L.2.2 PedigreeHow do Pedigrees help determine inheritance of

genetic traits and diseases?

Pedigrees

What is a pedigree?

-Pedigrees are family trees which show which individuals in the family get certain diseases or have certain traits.

Why are pedigrees important?

Scientists use pedigrees to track/trace the passing on of genes and traits over generations.

Pedigrees help determine how genetic diseases are passed through families

Pedigrees show generations – kind of like a family tree

Pedigrees show generationsEach row represents a generation

Generation 1

Generation 2

Generation 3

Pedigrees show gender

Shape Gender

circle Female

square Male

Pedigrees Show Marriage/ MatingA horizontal line connecting a circle and a square means the male and

female are “married”

Pedigrees show childrenVertical Line connect parents and

children

Parents

Children

Pedigrees shown Genotypes / Affectedness

shaded / colored = has trait

a colored in shape always has the recessive traitunless otherwise statedTwo lower cases in genotype

half shaded = carrier / heterozygous

Clear shape = homozygous dominant genotype

Heterozygous if child is colored inGenotype written as E? (letter and ?)

Shaded = homozygous recessive

Half = heterozygous

Clear = Homozygous Dominant or Heterozygous (depends on child’s genotype)

Pedigrees show Death

Circle or Square with diagonal line means person has died

http://www.youtube.com/watch?v=Wuk0W10EveU

Rules of Logic for Reading A Pedigree

1. If neither parent show the trait:• a. the trait cannot be dominant.• b. the trait could be recessive and either parent or both could be

heterozygous carriers.

2. If one parent shows the trait:• a. the trait could be dominant and the affected parent could be

heterozygous while the unaffected parent is not a carrier• b. the trait could be recessive and the affected parent is homozygous while

the unaffected parent could be a heterozygous carrier

3. If both parents show the trait:• a. the trait could be dominant and both parents could be heterozygous

carriers which• means that some of the children could be unaffected• b. the trait could be recessive meaning that both parents would have to be

homozygous and• all the children would have to be affected

Pedigree 1 shows a family of parrots. One of the offspring shows the trait for blue feathers. (R = red feathers, r = blue feathers)

1. Do you think blue feathers are dominant or recessive? recessive 2. What must the genotypes of the parents be?

3. What two genotypes could the other offspring have? RR or Rr

1. Father has green leaves2. Male = gg, female = Gg

1. Bb2. bb3. Bb or BB

Reading a Pedigree

1. How many males are there?

2. How many females are there?

3. How many children did the first generation parents have?

4. How many sets of married couplesDoes the pedigree show?

5. How many carriers does the pedigree show?

6. How many affected individuals does the pedigree show?

1. How many males are there? 4

2. How many females are there? 5

3. How many children did the first generation parents have? 3

4. How many sets of married couplesDoes the pedigree show?3

5. How many carriers does the pedigree show? 0

5. How many affected individuals does the pedigree show? 1

Practice

1. Genetics Pedigree Worksheet

#1 > no dimples = dd (colored in = no dimples)

#2 > unibrow = ee (colored in = unibrow)

#3 > colored in = dd

Warm Up

• Put Pedigree HW worksheet on desk

• Answer front side of handout (the side that says Warm Up)

READ KEY AT THE BOTTOM OF THE PAPER

Colored = FreeBlank = Attached

F = Dominant, Freef = Recessive, Attached

Review Exit TicketHow many generations?3

The chart shows a total of 5 female offspring. How many of these women are carriers of colorblindness? 2

Of the 3 male offspring, how many have colorblindness? 2

Table of Contents

March 20th Pedigree Day 2

How do you interpret a pedigree chart?

Identifying People in Pedigrees

Roman Number of Generation and then Number in row

Review HW

a. How many males are there? 8 b. How many males have hemophilia? 3

2. A circle represents a female. If it is darkened, she has hemophilia; if open she is normal.

a. How many female are there? 8 b. How many females have hemophilia? 2

3. A marriage is indicated by a horizontal line connecting a circle to a square. a. How many marriages are there? 3

4. A line perpendicular to a marriage line indicates the offspring. If the line ends with either a circle or a square, the couple had only one child. However, if the line is connected to another horizontal line, then several children were produced, each indicated by a short vertical line connected to the horizontal line. The first child born appears to the left and the last born to the right.

a. How many children did the first couple (couple in row I) have? 2 b. How many children did the third couple (couple in row III) have? 7

5. Level I represent the first generation, level II represents the second generation.

a. How many generations are there? 4 b. How many members are there in the fourth generation? 7

IIIIII

6. Write the generation on the pedigree numbers (roman numerals).

7. Which members of the family above are afflicted with Huntington’s Disease? I-1, II-2, II-3, II-7, III-3

8. There are no carriers for Huntington’s Disease- you either have it or you don’t.

With this in mind, is Huntington’s disease caused by a dominant or recessive trait? dominant

9. How many children did individuals I-1 and I-2 have? 6

10. How many girls did II-1 and II-2 have? 2 How many have Huntington’s Disease? 2

11. How is individual III-2 and II-4 related? niece-uncle

I-2 and III-5? grandma-grandson

12. Write the genotypes of each individual on the pedigree.

IIIIIIIV

13. Write the generation on the pedigree numbers (roman numerals). The pedigree to the above shows the passing on of Hitchhiker’s Thumb

in a family. Is this trait dominant or recessive? recessive

14. How do you know? Because parents III-4 and III-5 had to have kids IV-2 and IV-4

15. How are individuals III-1 and III-2 related? mating

16. Name 2 individuals that have hitchhiker’s thumb. IV-2 and IV-4

17. Name 2 individuals that were carriers of hitchhiker’s thumb. III-4 and III-5

18. Write the genotypes for each individual on the pedigree.

• 19

• a. Which characteristic is dominant? Black

• b. Which characteristic is recessive? White

• c. Determine the genotypes of all individuals. You will have three “A?”. Write your Genotypes beneath each individual.

Interpreting a Pedigree

Generations

- Each row represents a generation.- Each generation is marked using Roman

Numerals - (I, II, III, IV)

Interpreting a Pedigree

On a pedigree the trait is shown by the colored shapes

Generally if a shape is colored that person has the trait

Parent Genotype Based on Child

If one or more child has the trait

Parent shapes are blank

Parent genotype = heterozygous

Determining if the trait is Dominant or Recessive

If one parent has disorder (colored) disorder is dominant

If neither parent has to have the disorder (blank) but children do, the disorder is recessive and parents are heterozygous.

Parent with disorder (colored in) = dominant

Parent without disorder (blank) = recessive

Dominant

Recessive?

Dominant because

The father has it

Dominant or Recessive

Recessive because parents do not have it

Dominant or Recessive?

Recessive because parents do not have it

Dominant or Recessive?

Dominant because one parent has it

Practice

Problem 1 and Problem 2

Problem 1

1. I , II 1, II3, II 7, III3

2. Dominant

4. 2 Huntington's = 1

5. Uncle Grandmother1

Problem 2

1. Recessive

2. Because the parents do not have it

3. Married

4. IV 1, IV3

5. III 1, III 2

Problem 3

Create a pedigree for the following:

1. Joe Marries Sue- they are carriers for the jumping disease

2. They have 4 kids: Jack, Zack, Luke and Sara

3. Zack and Sara have the jumping disease (recessive)

4. Jack marries Amy, she has the disease

5. They have Lorie, who is also affected

6. Sara marries Dan who is a carrier. Sara is pregnant

B. Punnett Square

Sara = rr

Dan = Rr

There is a 50% chance

Their baby will have

The disease

r Rr rr

A. Make a pedigree for the family below. 1. Matt and Jennifer get married; Matt has hairy toes

(recessive)2. They have 2 kids, Adam and Faith3. Adam has hairy toes and Faith is a carrier4. Faith marries Alex. They have 1 son. He does not have

hairy toes.

B. What is Jennifer’s Genotype? How do you know?C. What is Alex’s Genotype? How do you know?

1. How many generations are in this pedigree?

2. Is the trait in this pedigree dominant or recessive?

3. What are the genotypes of III 5 and III 6?

4. How many males are in generation II?

5. How many females are there total?

Chromosomes Determine Gender

XX = Female

XY = Male

a trait that is found on either the X or Y

chromosome

Sex Linked Trait

Hemophilia is an example of a sex

linked trait.

a disease where your blood doesn’t

Hemophilia

Hemophilia only occurs when all of

the X chromosomes have a copy of the

recessive gene.

XHXh:female carrier XhXh:female hemophiliac

XHY:normal male XhY:hemophiliac male

SICKLE CELL ANEMIA

Difference between normal cells & sickle

Sickle Cell

ss = sickle cells

(lethal)

Ss = carrier (SC trait)

SS = normal

Sickle Cells tend to get stuck easily in the circulatory

system.

Why would African American’s be so

much more likely to have Sickle Cell?

Regular red blood cells infected by malaria

chart that shows the relationships within a family

PEDIGREE

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Sample Pedigree

Pedigree Basics• Males are squares, females are circles,

and unborn babies are triangles or octagons

• Shaded figures represent individuals with the trait, a carrier could be 1/2 shaded

• Generations are numbered with roman numerals (I, II, II, IV) from top to bottom

• People within generations are numbered (1,2,3) from left to right

a protein produced by white blood cells in the body in

response to the presence of an antigen, for example, a

bacterium or virus

ANTIBODY

a substance, usually a protein, on the surface of a cell or bacterium that

stimulates the production of an antibody

ANTIGEN

Blood group AYou have A antigens on the surface of your red blood cells and B antibodies in your blood plasma.

Blood group B You have B antigens on the surface of your red blood cells and A antibodies in your blood plasma.

Blood Groups

Blood GroupsBlood group ABYou have both A and B antigens on the surface of your red blood cells and no A or B antibodies at all in your blood plasma.

Blood group 0

You have neither A or B antigens on the surface of your red blood cells but you have both A and B antibodies in your blood plasma.

Rh FactorsMany people have a Rh factor on the surface of their red blood cells. This is also an antigen and those who have it are called Rh+. Those who haven't are called Rh-.

Possible Blood Groups

You can belong to either of following 8 blood groups:

A Rh+ A Rh-B Rh+ B Rh-AB Rh+ AB Rh-0 Rh+ 0 Rh-

Transfusions

QuickTime™ and aTIFF (LZW) decompressor

The transfusion will work if a person who is going to receive blood has a blood group that doesn't have any antibodies against the donor blood's

antigens.

People with blood group 0 are called "universal donors" and people with blood group AB

are called "universal receivers.

http://www.nobel.se/medicine/educational/landsteiner/index.html

PRACTICE TRANSFUSIONS

200 B.C.Humans “clone” trees by cuttings

1950Humans clone frogs

1980’s Humans clone mice!

1997HUMANS CLONE SHEEP!!!

1998 Humans clone 8 copies of a cow!!!

moving genes from one chromosome of one

organism to the chromosome of another

GENETIC ENGINEERING

“Fat” Gene

making an exact copy of another cell / organism

CLONING

Dolly—the first cloned sheep

Ian Wilmut, the dude that

did it

Check out this short movie that talks about cloning…

A dividing cell

Read NYTimes Article "Despite Warnings, 3 Vow to Go Ahead on Human

Cloning"

a. What did three proponents of human cloning announce on August 7, 2001?

b. Where did they make this announcement? c. Why did some scientists at the symposium object

to the proponents' announcement? d. Why did Dr. Alan Colman object to the research

by these proponents being done in secret? e. According to the article, what was the consensus

among the panel and most of those who testified before it?

Read NYTimes Article "Despite Warnings, 3 Vow to Go Ahead on Human

Cloning" f. Who was "Dolly"?g. What animals have been successfully cloned? h. According to the article, what is involved in cloning a human? i. How did the three proponents say they would

address the possibility of genetic abnormalities? j. How did other experts at the symposium respond

to this statement? k. Why do the proponents need to conduct their

research secretly?

•http://www.biology.washington.edu/bsa/karyotypeS.html

•http://worms.zoology.wisc.edu/zooweb/Phelps/karyotype.html

•http://www.biology.arizona.edu/human_bio/activities/karyotyping/karyotyping.html

•http://www.pathology.washington.edu/galleries/Cytogallery/cytogallery.html

•http://www.biology.iupui.edu/biocourses/N100/2k2humancsomaldisorders.html

A technique used to determine the genetic traits of a baby before it is

AMNIOCENTESIS

Klinefelter Syndrome• Have male genitalia and internal ducts, but

underdeveloped testes

• Do not produce sperm

• Slight enlargement of the breasts

• 47,XXY

• 1 out of every 500 male births

Turner Syndrome• Has female external genitalia

• Underdeveloped ovaries

• Short (under 5 feed)

• Webbed Neck

• Broad, Shield-like chest

• 45,X

• 1 out of every 3000 female births

Cri-du-Chat Syndrome• Partial monosomy (part of 1 chromosome is lost)• Loss of about 1/3 of the short arm of

chromosome 5• Anatomical malfomrations (gastrointestinal and

cardiac complications)• Mentally retarded• Abnormal development of the larynx which

makes the baby’s cry sound like a cat’s cry• 1 in 50,000 live births

Down Syndrome• BKA trisomy 21 (47, 21+); 3 copies of the 21st chromosome• Short• Small round heads• Protruding, furrowed tongues which cause mouth to remain partially

open• Retarded (IQ below 70)• Shortened life expectancy (<50)• Prone to reparatory disease and heart malformations• Have 15x higher chance of getting leukemia• Chance of having a baby with Down syndrome goes up as the

mother gets older

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