Making a Pedigree Chart

A family history of a genetic condition

Quick Review 1. Genotype =

2. Dominant genes are usually

represented by:

3. Lower case letters are used for:

4. For every trait, you get an _______from each

parent.

5. The genes you inherit are determined ____________.

a description of genes (two alleles) inherited for a particular trait

a capital letter

the recessive allele.

a allele

randomly

Making a Pedigree Chart • Pedigree charts are

made to chart family history and see how traits are passed

• A genetic counsellor will use pedigree charts to help determine the distribution of a disease in an affected family

Symbols

• Shade individuals that have the trait you’re studying

• Boys = squares (Lucy always calls Charlie Brown a ‘block head’)

• Girls = circles

• Married-connected at side

• Siblings-connected at TOP not at the side (hopefully not siblings AND married)

• Oldest child-to the left

• Question-if shaded individuals in this pedigree have blue eyes, what is the GENOTYPE of the parents?

Other • Divorced,

separated

• Deceased

• Identical twins

• Fraternal twins

Generations are identified by Roman numerals

Organizing the pedigree chart

I

II

III

IV

Organizing the pedigree chart

• Individuals in each generation are identified by Arabic numerals numbered from the left

• Therefore the affected individuals are II3, IV2 and IV3

I

II

III

IV

1 2 3 4 5 6 7

Flipnob Dimples • This is the story of Grandma and

Grandpa Flipnob, and their clan! They were married way back in 1933, and have been just like newlyweds ever since.

Flipnob Dimples pg 2 • From their union, 4 individuals were

created. Elizabeth, the eldest, was born in 1935. Fred soon followed in 1936. In 1939 Michelle was brought into this world. Mickey (a surprise to the whole family) was the baby of the family, not being born until 1950.

Flipnob Dimples pg 3 • Elizabeth fell in love at a young age,

and wed her high school sweetheart, David, in 1954. From this marriage, two bundles of joy came about (at the same time):

• John and Sonny - 1955 (twins)!

Flipnob Dimples pg 4 • It took Fred a little longer to find

his soul mate. Finally in 1970, Fred found the woman of his dreams, Wilma, and they were married. Since they married so late in life, they only brought one new person into this world:

• Barney - 1972

Flipnob Dimples pg 5 • Michelle was a hard working woman,

and never found time in her schedule for love. She led a very productive and fulfilling life, but she never did marry and have children.

• Answer the following questions regarding your pedigree:

• 1. Who are the inlaws?

• 2. What is the relationship between the people in the third generation?

• Now that you have your pedigree chart together, shade the appropriate circles and squared from the information to follow. Remember that individuals who possess the RECESSIVE trait are to be filled in. Those individuals not filled in possess at least one dominant trait.

•

From their union, 4 individuals were created. Elizabeth, the eldest, was born in 1935. Fred soon followed in 1936. In 1939 Michelle was brought into this world. Mickey (a surprise to the whole family was the baby of the family, not being born until 1950.

Flipnob Dimples

• Elizabeth fell in love at a young age, and wed her high school sweetheart, David, in 1954. From this marriage, two bundles of joy came about (at the same time):

• John and Sonny - 1955 (twins)!

Flipnob Dimples

• It took Fred a little longer to find his soul mate. Finally in 1970, Fred found the woman of his dreams, Wilma, and they were married. Since they married so late in life, they only brought one new person into this world: Barney - 1972

Flipnob Dimples

• Michelle was a hard working woman, and never found time in her schedule for love. She led a very productive and fulfilling life, but she never did marry and have children.

Flipnob Dimples

• Mickey was a wild one!! After a long string of girlfriends, he finally chose Monica to spend the rest of his life with. They were wed in 1975 and brought two girls into this world:

• Krista - 1977

• Janet - 1979

Flipnob Dimples

Make sure you have the Generations marked and the indivduals numbered.

1. Who are the in-laws?

2. What is the relationship between the people in the third generation?

Flipnob Dimples

• Now that you have your pedigree chart together, shade the appropriate circles and squared from the information to follow. Remember that individuals who possess the RECESSIVE trait are to be filled in. Those individuals not filled in possess at least one dominant trait.

Flipnob Dimples

• Now that you have your pedigree chart together, shade the appropriate circles and squared from the information to follow. Remember that individuals who possess the RECESSIVE trait are to be filled in. Those individuals not filled in possess at least one dominant trait.

Flipnob Dimples

• Not having freckles is a recessive trait.

• Grandpa Flipnob did not have freckles, but his beautiful bride did.

• Fred and Michelle were the only two of their siblings to have freckles.

• Of the grandchildren, the twins did not have freckles, and neither did Barney, but the two girls did.

Flipnob Dimples

• GUIDE

• STEP 1

• Assign two recessive genes to any person on the pedigree whose symbol is shaded. Small letters are written below the person s symbol.

• GUIDE

• STEP 2

• Assign one dominant gene to any person on the pedigree whose symbol is unshaded. A capital letter is written below the person s symbol. Add a short black line next to the capital letter.

• GUIDE

• STEP 3

• Use the information given to you to determine the second alleles for each person with the dominant phenotype.

http://www.slideshare.net/aus_autarch/pedigree-charts-powerpoint-presentation

Autosomal – Approx. 50/50 affected

Dominant– One parent has the disorder

Recessive – Neither parent needs to have the disorder they can be heterozygous

What’s going on? Shaded = blue eyes

• 1 and 2 split after having 4, 2 then had kids with 3 and split with her too after 5-9 were born

• Genotypes of 1, 4,7?

• Genotypes of 2 & 3?

• Genotypes of 5,6, 8, 9, 10, 11, 12?

Make your own pedigree • Using your own family, make your own

pedigree chart • Must at LEAST include grandparents,

parents, & your generation • Pick one easy dominant or recessive trait

and shade individuals that have it. You can guess who has it if you don’t know for sure. (Don’t pick a trait that EVERYONE in your family has)

• Label yourself, grandparents, cousins, etc • Put a key on the pedigree so I know

what shaded means. Ex.- shaded people have widow’s peak

OR…you may create a pedigree chart for a fictional family of your choice. For example, a family in a book you read or a movie you have seen (ex: Twilight series, Harry Potter, etc)