Pedigree & Punnett Square Homework (Due date: _______________)
Please staple this sheet to your answers.
Name ________________________________Anth 1 MW? TTh? Time:_____________
1. (5 points).
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Choose one Mendelian trait that someone in your family has.
o Use a colored marker (not yellow) to show me here which one you are
choosing from this list: widow’s peak, dimples, freckles, hitch-hiker’s thumb,
ABO blood type, Rh factor, sickle cell disease, hemophilia.
o See the back of this sheet for examples of traits on this list.
o Be sure to pick a trait you can find out about from people you see often.
Make a pedigree for your extended family but do not put their names. Include at least
three generations and some cousins. Don’t include traits yet. It’s okay to leave some
people out.
o Use the conventions presented in class and in the book.
o Watch out for “virgin births” and “incest” – common mistakes.
o For divorce, put a slash through the mating line.
o For a death, put an X through the circle or square.
o For remarriage, just add another spouse.
o Yes, these things get complicated and messy in real life!
If you are adopted or estranged from your birth family, make a fictional pedigree that
works with the rules of heredity, shows 3 generations and some cousins, and uses the
conventions. Since there are no names on any pedigrees, I won’t know which
students did birth families or not.
Once your pedigree is complete, then show the relevant phenotypes for individuals.
o Show dominant phenotypes by filling in the shape (solid); recessive with no fill.
o For relatives with unknown traits, put a question mark in their circle or square.
2. (5 points).
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Pick one couple from your pedigree that had kids and circle them with a colored
marker (not yellow).
Do a Punnett Square for that couple.
o Use the alleles shown on the back of this sheet for the trait you choose.
o Remember that folks with a dominant phenotype could be heterozygous.
o Choose genotypes for the parents that could result in the traits of the kids.
On the pedigree, use a colored marker (not yellow) to circle one offspring of this
couple that has a genotype found inside your Punnett Square.
Trait
Expression of
dominant allele
Phenotype of
recessive homozygote
Use these
alleles
Widow’s peak
W, w
Dimples
D, d
Freckles
F, f
Hitch-hiker’s (bent)
thumb
B, b
ABO blood type
See class notes and textbook
Rh factor
See class notes and textbook
Sickle cell
See class notes and textbook
Hemophilia
See class notes and textbook
A, B, O
Rh+, RhHbA, HbS
XH, Xh, Y
If you want to do another trait in your family, check with me. It cannot be earlobes, cleft
chin, tongue rolling, eye color, skin color, hair color, diabetes, or cancer since these are
polygenic, environmentally influenced, and/or have incomplete penetrance.