Download Pedigree Charts

NAME_________________________________PERIOD_________DATE_____________________
Pedigree Charts
All living things have pedigrees. A pedigree is a diagram that shows the occurrence and appearance
(phenotype) of a particular genetic trait, as it is passed from one generation to the next in a given family.
From this information, along with an understanding of inheritance, genotypes of individuals can often be
determined.
Pedigree 1 traces the dimples trait through three generations of a family. Blackened symbols represent
people with dimples. Circles represent females and squares represent males.
I
1
2
3
4
4
5
II
1
2
3
III
1
The following passage describes the family shown in Pedigree 1.
Although Jane and Joe Smith have dimples, their daughter, Clarissa, does not. Joe’s dad has dimples,
but his mother, and his sister, Grace, do not. Jane’s dad, Mr. Renaldo, her brother, Jorge, and her sister,
Emily, do not have dimples, but her mother does.
1. Write the name of each person below the correct symbol in Pedigree 1.
2. How is marriage symbolized?______________________________________________________
3. How are offspring symbolized? ____________________________________________________
4. What do the Roman numerals mean?_______________________________________________
5. On a separate piece of paper, make a pedigree based on the following passage:
Pedigree 2: Ben, Louise, and Matt have freckles, but their mother, Mrs. Cummins, does not. Mrs.
Giordano, Mrs. Cummins’s sister, has freckles, but her parents, Mr. & Mrs. Lutz, do not. Elizabeth and
Sue Giordano are freckled, but their sister Harriet, like her father, is not freckled.
6. What advantages does a pedigree have over a written passage?
CNICHOLS2006
Original Source: Pedigree Chart Activity by Heidi Tither and Melanie Norton
NAME_________________________________PERIOD_________DATE_____________________
Create a Pedigree Chart for the following scenario:
Pedigree 3
This is the story of Grandma and Grandpa Chadwick, and their clan! They were married way back in
1933, and have been just like newlyweds ever since. 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.
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 in 1955 (twins)!
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 in 1972
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.
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 in 1977 and Janet in
1979
Answer the following questions regarding Pedigree 3:
1. Place a name below to each circle or square.
2. Who are the in-laws?
3. What is the relationship between the people in the third generation?
DETERMINING PEDIGREE WITH ONE TRAIT:
Trait: Freckles
Freckles is a DOMINANT trait –shade in circle or square
No freckles is a RECESSIVE trait-leave blank (no shading)
Grandpa Chadwick did not have freckles, but his beautiful bride did. Fred and Michelle were the only
two of the siblings to have freckles. Of the grandchildren, the twins did not have freckles, and neither
did Barney, but the two girls do.
DETERMINING GENOTYPE:
Now: Using the guide provided, determine the genotypes of all individuals in this pedigree chart for
freckles. Remember, having freckles is a DOMINANT trait and not having freckles is a RECESSIVE
trait.
Write the genotype below each person’s symbol.
Assign two recessive alleles to any person on the pedigree whose symbol is unshaded. (ff)
Assign one dominant gene to any person on the pedigree whose symbol is shaded. A capital letter is
written below the person s symbol. (F__)
Use the information given to you to determine the second alleles for each person with the dominant
phenotype.
CNICHOLS2006
Original Source: Pedigree Chart Activity by Heidi Tither and Melanie Norton
NAME_________________________________PERIOD_________DATE_____________________
QUESTIONS (Create a Punnett Square to determine the answer for each question)
1. From your results, what is Grandma’s genotype? ____________________
2. What must be the genotypes of their children?
We know that Grandpa Chadwick is homozygous recessive.
3. If Grandma were homozygous dominant, could any homozygous recessive children be produced
from Grandma and Grandpa?
4. If Grandma was heterozygous, could any homozygous recessive children be produced from
them?
SEX-LINKED INHERITANCE - COLORBLINDNESS
To complete this part of the activity, you will need to make a copy of your Pedigree 3 chart. (Do not fill
in any circles or squares)
Remember to determine the genotypes of those possessing the sex-linked trait first. From there, using
Punnett squares, you should be able to determine the genotypes of most, if not all of the family.
Neither Grandma nor Grandpa Chadwick is colorblind.
All of their children have normal color vision, except for Mickey.
Of the grandchildren, the twins both inherited colorblindness, as did their cousins, Barney and Janet.
There still remains one colorblind person in this clan, however, that is up to you to determine who.
Identify the genotype for each individual in the Chadwick family for colorblindness?
CNICHOLS2006
Original Source: Pedigree Chart Activity by Heidi Tither and Melanie Norton