Name ________________________________________________Period _____________ Date: ________________
Pedigree Analysis
Chapter 7
Objective
In this investigation you are to analyze two family pedigrees and determine whether the gene for the trait
listed is dominant or recessive and determine the genotype of each individual in the family.
Procedure
1. For each pedigree, identify the genotypes of the people indicated in them. Example: DD, Dd, D___, or dd.
If you determine that the person is a carrier, shade their box in half-way on the pedigree.
Pedigree A: Deaf Mutism
One form of deafness in humans is a type in which the individual inherits not only deafness but also the
inability to talk. Use symbols D for dominant and d for recessive. Place the genotype for each person in the blank
that corresponds to their place in the pedigree.
I-1 Dd
I-2 Dd
II-1 Dd
II-2 Dd
II-3 D__
II-4 Dd
II-5 Dd
III-1 D__
III-2 dd
III-3 dd
III-4 D_
III-5 D_or DD III-6 D_ or DD III-7 D__
III-8 dd
III-9 D_or DD III-10 D_
III-11 dd
III-12D_ or DD III-13 dd
IV-1 dd
IV-2 dd
IV-3 dd
IV-4 D_or DD III-5 D_ or DD IV-6 D_ or DD IV-7 Dd
IV-8 Dd
IV-9 Dd
IV-10 Dd
IV-11 Dd
IV-17 dd
IV-18 dd
II-6 D__
II-7 dd
II-8 dd
IV-15 dd IV-16 dd
IV-12 Dd
IV-13 Dd
III-14 dd
IV-14 Dd
I put D_ initially on all of these listed above that are white but I can see why you might but
DD…is okay
Pedigree B: Hemophilia
Hemophilia is a disease of the circulatory system. It is sometimes called bleeder’s disease because persons
with the disease have a very slow clotting time when injured. An affected person could bleed to death from minor
wounds or internal injuries. Use symbols R for dominant and r for recessive. Place the genotype for each person
in the blank that corresponds to their place in the pedigree. Note: Hemophilia is a sex-linked trait.
Males = XRY = normal, XrY = hemophiliac
Females = XR XR= normal, XR Xr = carrier, XR X---- = unknown genotype, Xr Xr = hemophiliac
I-1 XR Xr
I-2 XRY
II-1 XrY
II-2 XR Xr
II-8 XR Xr
II-9 XRY
III-1 XR Xr
III-8 XrY
II-3 XR X----
II-4 XR Xr
II-5 XrY
II-6 XRY
II-7 XR X----
III-2 Xr Xr
III-3 XRY
III-4 XR X----
III-5 XR Xr
III-6 XRY
III-7 XR Xr
III-9 Xr Xr
III-10 Xr Xr
III-11 XR X----
III-12 XR X----
III-13 XRY
III-14 XRY
III-15 XR X---- III-16 XrY
III-17 XRY
III-18 XR X----
IV-1 XR X---- IV-2 XR X----
IV-3 XRY
IV-4 XRY
IV-5 XR X----
IV-6 XrY
IV-7 XR X----
IV-8 XRY