Genetics Problems
Chapter 7 Lab Exercise A,
individual, 20 points
Please read Chapter 7 of What is Life? A Guide to Biology before beginning this lab.
The purpose of this lab exercise is to gain experience working monohybrid and dihybrid crosses. This
will provide a greater understanding of how genes are passed from parents to offspring.
For this lab exercise, work the following genetics problems and answer the questions. A Punnett square
may be needed for some of the problems. You may answer the questions electronically on this Word
document. You may also work the problems on paper, scan or photograph the paper pages, and submit
these pages electronically. Read the questions clearly since all information needed to work the problems
and answer the questions is provided in the question. Use the uppercase (capital) letter to indicate a
dominant allele. Use the lowercase letter to indicate a recessive allele. We will also assume that
mutations are not occurring in the genetics problems.
1. Albinism (lack of skin pigmentation) is caused by a recessive autosomal allele. Autosomal alleles are
those found on chromosomes other than the sex chromosomes. This would be chromosome number 1-22
in humans. A man and woman, both normally pigmented, together have an albino child. P = allele for
pigmentation, p = allele for albinism.
a. For this trait, what is the genotype of the albino child? Can you be certain? Why?
The genotype of the child is pp because it has inherited both recessive traits from the parents since it is
albino. Yes, I am certain because there is no other way for the child to be albino without both recessive
traits. If the child had even one dominant trait, then it would be normally pigmented.
b. For this trait, what is genotype of the mother? Can you be certain? Why?
It could either be PP or Pp because since she is normally pigmented, she must have at least one dominant
trait. I am certain because she is normally pigmented meaning that she has at least one dominant trait.
c. For this trait, what is the genotype of the father? Can you be certain? Why?
It could also either be PP or Pp because since he is normally pigmented, he must have at least one
dominant trait. I am certain because he is normally pigmented meaning that he has at least one dominant
trait.
2. In peas, tall (T) is dominant over the allele for short (t). What would you expect in the F 1
generation if you crossed a homozygous tall plant with a short plant? Why?
T T
In the F1 generation, I would expect all possible offspring
genotypes to be heterozygous Tt as the parents were tall
t Tt Tt
(homozygous TT) and short (homozygous tt). The offspring would
be tall as they carry at least one tall (T) trait.
t Tt Tt
This study source was downloaded by 100000900231380 from CourseHero.com on 07-28-2025 03:11:54 GMT -05:00
https://www.coursehero.com/file/37989927/Chapter-7-Genetics-Problems-Adocx/
Chapter 7 Lab Exercise A,
individual, 20 points
Please read Chapter 7 of What is Life? A Guide to Biology before beginning this lab.
The purpose of this lab exercise is to gain experience working monohybrid and dihybrid crosses. This
will provide a greater understanding of how genes are passed from parents to offspring.
For this lab exercise, work the following genetics problems and answer the questions. A Punnett square
may be needed for some of the problems. You may answer the questions electronically on this Word
document. You may also work the problems on paper, scan or photograph the paper pages, and submit
these pages electronically. Read the questions clearly since all information needed to work the problems
and answer the questions is provided in the question. Use the uppercase (capital) letter to indicate a
dominant allele. Use the lowercase letter to indicate a recessive allele. We will also assume that
mutations are not occurring in the genetics problems.
1. Albinism (lack of skin pigmentation) is caused by a recessive autosomal allele. Autosomal alleles are
those found on chromosomes other than the sex chromosomes. This would be chromosome number 1-22
in humans. A man and woman, both normally pigmented, together have an albino child. P = allele for
pigmentation, p = allele for albinism.
a. For this trait, what is the genotype of the albino child? Can you be certain? Why?
The genotype of the child is pp because it has inherited both recessive traits from the parents since it is
albino. Yes, I am certain because there is no other way for the child to be albino without both recessive
traits. If the child had even one dominant trait, then it would be normally pigmented.
b. For this trait, what is genotype of the mother? Can you be certain? Why?
It could either be PP or Pp because since she is normally pigmented, she must have at least one dominant
trait. I am certain because she is normally pigmented meaning that she has at least one dominant trait.
c. For this trait, what is the genotype of the father? Can you be certain? Why?
It could also either be PP or Pp because since he is normally pigmented, he must have at least one
dominant trait. I am certain because he is normally pigmented meaning that he has at least one dominant
trait.
2. In peas, tall (T) is dominant over the allele for short (t). What would you expect in the F 1
generation if you crossed a homozygous tall plant with a short plant? Why?
T T
In the F1 generation, I would expect all possible offspring
genotypes to be heterozygous Tt as the parents were tall
t Tt Tt
(homozygous TT) and short (homozygous tt). The offspring would
be tall as they carry at least one tall (T) trait.
t Tt Tt
This study source was downloaded by 100000900231380 from CourseHero.com on 07-28-2025 03:11:54 GMT -05:00
https://www.coursehero.com/file/37989927/Chapter-7-Genetics-Problems-Adocx/
