A Family Pedigree – Mini Project
Background: All of the conclusions regarding gene action
(dominant/recessive, codominant, incomplete dominance, etc) we have
discussed so far have been obtained from analyzing the results of
controlled crosses. In some situations, we do not have the opportunity to
perform controlled crosses. Instead, we must analyze an existing
population. This is always the case when studying human genetics.
Scientists have devised another approach, called pedigree analysis, to
study the inheritance of genes in humans and trace a trait throughout
generations.
Objective: Your task over the Thanksgiving break is to conduct research and trace a trait throughout at least
three generations of a family. **You may trace a trait throughout your own family, a famous family (English
royal family, Kardashians, Duck Dynasty, etc), or throughout a fictional family (Weasley, Baggins, Spongebob,
etc).**
Assignment Requirements:
-
Select and research a trait controlled by a SINGLE GENE
o Choose one of the following: Widow’s peak, dimples, freckles, hitchhiker’s thumb,
free/attached earlobes, tongue rolling, crossing of thumbs, or hairy knuckles.
o Google if the presence of your chosen trait is dominant or recessive
o Do NOT choose traits like eye color, hair color, or skin color
-
Collect your data and record the results of at least three generations
o Must have data for at least 10 individuals
o If researching your own family, you should be a member of one of the generations.
Data Collection Example:
***You must have your research data in
class on November 30. ***
Name
Grandma Sue
Trait
Can roll tongue
Grandpa Bill
Cannot roll tongue
Mom (Tami)
Can roll tongue
Dad (Chuck)
Can roll tongue
Me!
Can roll tongue
Brother Sam
Cannot roll tongue
Uncle Steve
Cannot roll tongue
Aunt Lori
Can roll tongue
Cousin Lauren
Can roll tongue
Cousin John
Can roll tongue
Pedigree Directions:
Your family pedigree assignment is due on FRIDAY, DECEMBER 4. You may trace a trait
through your family, another family, a fictional family, or a historical family. The important
thing is that your pedigree shows relationships correctly and that the genotypes of each
individual makes sense (in terms of dominant and recessive alleles).
Assignment Requirements:
- Trace a trait controlled by a single gene (google! Widows peak, dimples, freckles, hitchikers thumb, etc).
- Your pedigree must have at least THREE generations of people, with at least TEN individuals.
- Write the names of all individuals.
- Make a key!
State whether the trait is dominant or recessive.
State the phenotype for each genotype.
(Example: WW = Widows peak, Ww = Widows peak, ww = no widows peak)
- Write the genotypes over every individual. Represent unknown genotypes with a Question Mark ( ? )
- Not sure how to show something? Google "pedigree key" and you will get the answer for any situation (death,
adoption, divorce, twins, etc.)
- Make sure your paper is nice and neat. It may be handwritten or typed and done on any paper - notebook,
printer, poster...I don't care, as along as it does NOT appear sloppy and thrown together at the last minute.
Have fun with it!
Family Pedigree Assignment Rubric
The family pedigree includes…
- 3 generations of individuals ________ / 2 points
- At least ten individuals ________ / 2 points
- A key ________ / 1 point
Family Relationships
- All family relationships shown correctly ________ / 5 points
Genetic Understanding
- Genotypes are given and accurate for all individuals, with “?” used
only for unknown alleles ________ / 10 points
- In terms of genetics, genotypes make sense ________ / 3 points
Neatness
- Project appears neat and organized ________ / 2 points
TOTAL POINTS EARNED : ______________ / 25 POINTS