Biology Genetics Review
Name ___________________________
1. Who is the “Father of Genetics”? ________________________________
Match the definition with the appropriate Mendelian Law:
2. Pairs of alleles separate in meiosis, and each gamete
A. Rule of Dominance
receives one allele of each pair
B. Law of Segregation
3. One trait is dominant over another, if the dominant trait
C. Law of Independent Assortment
is present the other will be hidden
4. Sometimes traits disappear then reappear in a new generation
showing chromosomes are separated independently of one another
MONOHYBRID CROSSES
In mice, Brown fur (B) is dominant to white fur (b).
5. What is the genotype of a homozygous dominant mouse? _________
6. What is the genotype of a homozygous recessive mouse? _________
7. What is the genotype of a heterozygous mouse? ____________
8. Which genotypes could represent a brown mouse?
BB
Bb
bb
9. Which genotype must represent a white mouse?
BB
Bb
bb
10. Cross a white mouse with a heterozygous brown mouse.
What is the white mouse’s genotype: ___________
What is the heterozygous brown mouse’s genotype: ____________
Now, create the punnett that shows the crossing of these two mice and show genotype and phenotype
percentage possibilities for their offspring.
Genotypes:
BB: ___________
Bb: ___________
bb: ____________
Phenotypes:
Brown: ___________
White: ____________
11. Cross two heterozygous brown mice.
What is the genotype of the heterozygous female: ___________
What is the genotype of the heterozygous male: _____________
Now, create the punnett that shows the crossing of these two mice and show genotype and phenotype
percentage possibilities for their offspring.
Genotypes:
BB: ___________
Bb: ___________
bb: ____________
Phenotypes:
Brown: ___________
White: ____________
12. If I flip a coin, what are my chances of getting heads? _________ Tails? ___________
13. If a woman gives birth to a child, what are the chances she will have a boy? ________ Girl? _______
14. Mrs. Davis’ grandparents gave birth to 6 daughters. If they were still having kids, what is the chance
that their next child would have been a girl? (Be careful about this…) ____________
DIHYBRID CROSSES
Some genes are inherited together and can be shown in a dihybrid cross.
15. In plants green peas (G) are dominant to yellow (g), and rough texture (R) is dominant to smooth (r). If
a male parent plant has the genotype GgRr, what possible allele mixtures could be in the sperm of the
parent for these two genes? Complete the Punnett below then fill in the sperm with allele combinations.
Transfer the genotype from the punnett to the sperm picture and write underneath the sperm the phenotype of the genes it is
carrying. The first one has been done for you.
G
R
g
GR
GR
Green, rough
r
16. In apple trees, having apples (A) is dominant to not having apples (a) and having branches (B) is
dominant to not having branches (b). Look at the dihybrid cross below. What are the genotypes and
phenotypes of the squares labeled? The first one has been done for you as an example.
Genotypes:
a. AABb
b. _____________
c. _____________
d. _____________
Phenotypes:
A. Apples, Branches
B. __________________________________
C. __________________________________
D. __________________________________
A
B
C
D
18. Jane has red hair (h) but her parents have brown hair (H). What must her parent’s genotypes be in order
for her to have red hair?
19. A mouse has 8 babies. 4 of the babies are black and 4 are white. What must the parent’s genotypes be
in order to produce this litter of babies?
PEDIGREES
Use the pedigree below to answer the questions.
This pedigree is for red hair which is recessive
and is NOT sex-linked. Brown hair (H) is
dominant to red hair (h).
20. What is the gender of person II-1?
___________________
21. What is the gender of person II-2?
____________________
22. How many children did II-2 and II-3
have? ____________
23. How many sons did I-1 & 1-2 have?
____________________
24. What is the genotype of person labeled
I-2? ___________
25. What is the genotype of the person labeled I-4? ___________
26. What is the genotype of person II-2? ______ (You must look at the person’s children to figure this out)
27. What is the genotype of person II-3? ______ (You must look at the person’s children to figure this out)
28. If person III-3 marries a person who is heterozygous for hair color, what are the possible hair colors seen
in their kids?
What is person III-3’s genotype? ________ What is a heterozygous person’s genotype? __________
Put these two genotypes around the Punnett to determine hair color possibilities for their kids.
INCOMPLETE DOMINANCE
In flowers, red petal color (RR) is incompletely dominant to white petal color (R’R’) producing a new
phenotype of pink petal color (RR’).
29. Cross a red flower with a white flower and show genotypes and phenotypes of offspring.
Genotypes:
RR _________
RR’ ________
R’R’ ________
Phenotypes:
Red- ____________
Pink- ___________
White- __________
30. Cross two pink flowers and show genotypes and phenotypes of offspring.
Genotypes:
RR _________
RR’ ________
R’R’ ________
Phenotypes:
Red- ____________
Pink- ___________
White- __________
CODOMINANCE
In chickens, black feathers (BB) is codominant to white feathers (WW) creating a new phenotype of Black
and White Checkered feathers (BW).
31. Cross a white feathered chicken with a black and white checkered chicken and show genotypes and
phenotypes.
Genotypes:
BB _________
BW ________
WW ________
Phenotypes:
Black ____________
Black & White- ___________
White- __________
32. Cross two black and white checkered chickens and show genotype and phenotypes.
Genotypes:
BB _________
BW ________
WW ________
Phenotypes:
Black ____________
Black & White- ___________
White- __________
MULTIPLE ALLELES
33. Fill in the chart below with the possible genotypes of the blood types listed.
PHENOTYPES
Blood Type A
Blood Type B
Blood Type AB
Blood Type O
GENOTYPES
34. Would you say a person with a genotype of AA is homozygous or heterozygous? ______________
35. Would you say a person with a genotype of AO is homozygous or heterozygous? _______________
36. Is blood type AB an example of incomplete dominance or codominance? ______________________
37. Which blood type seems to be more recessive- A, B, or O? _________________________________
38. Cross a parent with O blood with a parent with AB. What are the possible blood types for their kids?
Blood Phenotypes:
_____________________
_____________________
39. Cross a parent with BB blood with a parent with OO blood. What are the possible blood types for their
kids?
Blood Phenotypes:
_____________________
40. Cross a parent with BO blood with a parent with OO blood. What are the possible blood types for their
kids?
Blood Phenotypes:
_____________________
_____________________
41. Suppose a mother with A blood produced a child with O blood. (The father is OO), what genotype must
the mother be to produce a child with O blood?
A
Mom
?
O
Dad
O
OO
child
A
SEX-LINKED TRAITS
Sex linked traits are found on the X chromosome.
Look at the chromosomes shown to the right.
42. Which pair belongs to a girl? _________
43. What is a girl’s genotype? ___________
44. Which pair belongs to a boy? ________
45. What is a boy’s genotype? ___________
46. The band across the tall chromosomes in both pictures
represents an allele for a sex-linked trait. What is different
about the bands on the boy’s chromosomes?
_______________________________________________
47. Can a boy be a carrier of a sex-linked trait? ______________ Why or
why not? __________________________________Look at the
Punnett to the right. Do boys get their X’s from their moms or dads?
______________________________________________________
B
48. Who gives a boy his sex-linked trait/disorder- his mom or dad? ______________________________
Hemophilia (h) is a recessive sex-linked blood disorder. Answer the following questions based on this
information. The first one has been done for you.
49. What is the genotype of a homozygous normal female? XHXH
50. What is the genotype of a heterozygous female? _____________
51. What is another name for a heterozygous female? ___________________________
52. What is the genotype of a homozygous recessive female that has hemophilia? ______________
53. What is the genotype of a normal male? _______________________
54. What is the genotype of a hemophiliac male? ______________
55. Cross a homozygous dominant female with a hemophiliac male. Answer the questions below
a. What are the chances of getting a CHILD with hemophilia? _____________
b. What are the chances of getting a GIRL that is a carrier? ________________ (remember, you
have to cover up the boys boxes, to answer questions about girls only)
56. Choose a male and female offspring from the Punnett Square above in question 52 and mate them. Use
a Punnett square to show the results of their offspring. Answer the questions that follow.
a. What are the chances of getting a CHILD with hemophilia? _____________
b. What are your chances of getting a BOY with hemophilia? _______________ (remember, you
have to cover up the girls boxes, to answer questions about boys only)
c. What are the chances of getting a GIRL
that is a carrier? ________________
57. What is the genotype of person I-1?
______________
58. What is the chance of person I-1 passing the
disease to their offspring? ______________
59. Suppose person II-2 and II-3 have another child.
What is the chance they will have a GIRL with
hemophilia? (Do a Punnett) _____________
60. What is the chance they will have a CHILD with
hemophilia? ____________
61. Other than looking at the title of the picture, how
else would you have known this pedigree was for
a sex-linked disorder?
MUTATIONS & DISORDERS
Match the mutation name with the picture.
62. Insertion
63. Deletion
64. Duplication
65. Inversion
Match the type of mutation to the picture.
66. Point mutation
67. Frameshift
68. nondisjunction
B
A
C
Match the disorder to its description.
69. Child cannot drink milk b/c he can’t break down phenylalanine
70. Person has abnormal shaped red blood cells, severe pain & clots
71. Person’s sex chromosomes are XXy
72. Person has mucus build up in lungs and digestive system
A.
B.
C.
D.
Klinefelters
Cystic fibrosis
Sickle Cell
PKU
Match the disorder to its description.
73. Child has fat build up in nerve cells, loses ability to function, dies before age 8
74. Adult male loses feeling in arms legs, dies before age 40
75. Child born with shortened arms and legs, normal head & chest region
76. Female has sex chromosomes XO, webbed neck, mild mental deficiency
A.
B.
C.
D.
Turners
Achondroplasia
Huntington’s
Tay Sachs Disease
Use the karyotype picture to the right to answer the following questions:
77. Is this person a boy or girl? __________
78. Circle the sex chromosomes.
79. What are all the other chromosomes called?
___________________
80. Is the person in the karyotype to the right a boy or
girl? ________________
81. This person is not normal. Look over the
chromosomes and find the abnormality. What
genetic disorder does this person have?
___________________________________
82. What type of mutation causes this genetic disorder?
a. Point mutation
b. Frameshift mutation
c. Nondisjunction