Download Sex-Linked Traits

Genetics Part 2 Test Review
Codominance/Incomplete Dominance/Multiple Alleles/Polygenic Traits
1. What is Codominance? Give an example from the notes.
__________________________________________________________________________________________
__________________________________________________________________________________________
2. What is incomplete dominance? Give an example from the notes.
__________________________________________________________________________________________
__________________________________________________________________________________________
3. Blood typing is a common example of codominance. Show a Punnett Square with a parent who has AA
blood and a parent who has BO blood.
4. In the Punnett Square above, what are the TWO dominant alleles? What is the recessive allele?
______________________________________________________________________________________
5. In the notes we looked at Snapdragons. Show a Punnett Square for a heterozygous (pink) snapdragon
crossed with a recessive (white snapdragon).
6. In the Punnett Square above, what percent of the offspring are white? What percent are pink? What is the
phenotypic ratio? _____________________________________________________________________
7. What is the definition of the term multiple alleles? Give an example from the notes.
______________________________________________________________________________________
8. What is the definition of polygenic inheritance? Give an example from the notes.
_______________________________________________________________________________________
9. When examining blood types, how many phenotypes do we find? (circle one)
2
3
4
Genetics Part 2 Test Review
Sex-Linked Traits
1. A sex-linked trait is usually found on which chromosome (circle one)
X
Y
2. Why do certain conditions have a higher incidence (more individuals have the condition) in males?
__________________________________________________________________________________________
__________________________________________________________________________________________
3. If a female is homozygous for a sex-linked trait, what will happen to her male offspring?
__________________________________________________________________________________________
4. Colorblindness is a sex-linked trait. Show a Punnett Square for a mom that is heterozygous for colorblindness and a dad who is colorblind.
5. What percentage of their male children will be colorblind? _______________________________
Karyotypes
1. What is a karyotype?
_________________________________________________________________________________________
2. Why is a karyotype important?
__________________________________________________________________________________________
3. How can you see a Trisomy disorder on a karyotype?
__________________________________________________________________________________________
Pedigrees
1. What is a pedigree? ______________________________________________________________________
2. Why is a pedigree useful? __________________________________________________________________
3. What does a square represent in a pedigree? __________________________________________________
4. What does a circle represent in a pedigree? ___________________________________________________
5. What does a shaded shape represent? _______________________________________________________
Genetics Part 2 Test Review
Genetic Disorders
1. What is nondisjunction? _________________________________________________________________
2. What can nondisjunction result in? ________________________________________________________
3. Give an example of nondisjunction. _______________________________________________________
4. Could nondisjunction be identified on a karyotype? _____________
5. Where do genetic disorders occur? _______________________________________________________
FLASHBACK SECTION:
Dihybrid Crosses/Gene Expression/Meiosis
Use the dihybrid cross below to answer the questions.
R = round, r = wrinkled, Y = yellow, y = green
RrYy x RRyy
1. What is the probability of an offspring being round? ___________________________
2. What is the probability of an offspring being yellow? ___________________________
3. What is the phenotypic ratio in this dihybrid? ___________________________
Genetics Part 2 Test Review
4. What would the phenotypic ratio be if the cross was RrYy x RrYy? _______________________
5. Can the environment influence how genes are expressed? _____________________________________
6. What percentage of genes comes from mom? _______________________
7. What percentage of genes comes from dad? ________________________
8. Are the cells made in meiosis haploid or diploid? ______________________
9. How do we note that? (circle one)
2n
n