Download Bowman Pedigree Project

Bowman Family Pedigree Project
The Bowman Family has some interesting genetic traits. The family consists of Mom,
Dad, and nine Bowman kids. Some of the Bowman kids have albinism, a genetic
condition characterized by a lack of pigment which results in extremely light skin, hair,
and eyes.
Here are some details about the phenotypes of the Bowmans:
Name
Parents
Mom
Dad
Children (in order, eldest to
youngest)
Billy
Mike
Betsy (Ms. Bowman)
Meg
Tricia
JJ
Chris
Bobby
Peter
Phenotype
Possible genotype(s)
for albinism
light brown hair, green eyes
dark brown hair, blue eyes
light brown hair, brown eyes
has albinism
has albinism
light brown hair, hazel eyes
has albinism
dark brown hair, blue eyes
dark brown hair, brown eyes
dark brown hair, blue eyes
light brown hair, blue eyes
Here’s a recent picture of the whole Bowman family (Mom and Dad Bowman are on the
right, and there are a few in-laws in there too) :
Instructions:
 Answer each question completely.
 Show all work and answers neatly on a separate piece of paper.
 Turn in this packet AND your work.
1. Determine the inheritance pattern for albinism. Is it dominant or recessive?
Explain in detail your reasoning for your answer.
2. Fill in the “Genotypes” column of the table on the front page of the packet. If
there is more than one possibility, write both.
3. Given these genotypes and inheritance patterns, what proportion of the children
would you have predicted would have albinism? How closely do the actual
numbers of children match your predictions? Is this expected or unexpected?
Why?
4. Dark brown hair (D) is dominant over light brown hair (d). Blue eyes (e) are
recessive, so anyone with another color has at least one dominant allele (E).
a) Make a table listing each person in the family who doesn’t have albinism,
and their genotypes for the hair and eye genes.
b) Make a Punnett square (a big one!) showing predicted ratios of genotypes
and phenotypes for hair and eye color in the Bowman children, based on
their parents’ genotypes.
c) How closely do the actual numbers of children match these predictions?
5. Genetic counseling. Imagine that Mike, Ms. Bowman’s older brother, meets the
woman of his dreams. She does not have albinism, and has no history of albinism
in her family.
a) What is her most probable genotype?
b) Assuming you are correct about her genotype, what are the chances that
she and Mike will have…
 A child with albinism?
 A child who is a carrier for albinism?
6. More genetic counseling. Now imagine that Trisha, Ms. Bowman’s younger
sister, meets the man of her dreams. He does not have albinism, but he has a
brother who does.
a) What are the chances that this man of Trisha’s dreams is a carrier for
albinism?
b) What are the chances that they will have a child who has albinism?