1 | Page
Genetics Questions and Correct Answers
T/F
Mendel's law of segregation is supported by a 1:1 testcross ratio.
Ans: True
T/F
The non-functional form of a gene is called a wild-type allele. Ans:
False
T/F
© 2025 All rights reserved
, 2 | Page
A gene can have maximum two alleles. Ans: False
T/F
To test Mendel's Law of Independent ASsortment, the
experimenter needs a minimum of two different genes and their
two alleles. Ans: True
T/F
A 1:1 phenotypic ratio is expected from a monohybrid testcross
with complete dominance Ans: True
What phenotypic ratios are likely to occur in crosses when dealing
with two completely dominant, independently segregating gene
pairs, when both parents are heterozygous? Ans: 9:3:3:1
© 2025 All rights reserved
, 3 | Page
Provide simple definitions that distinguish segregation and
independent assortment. Ans: Segregation is the separation of
alleles during meiosis, while independent assortment states that a
member of one gene pair has an equal and independent
opportunity of segregating with either member of another gene
pair.
In Chi-square analysis, what condition causes one to reject the
null-hypothesis? Ans: When the probability value is less than
0.05.
Assuming a typical monohybrid cross in which one allele is
completely dominant to the other, what ratio is expected if the
F1's are crossed? Ans: 3:1
Under what conditions does one expect a 1:1:1:1 ratio? Ans: in a
cross involving doubly heterozygous individuals crossed to fully
recessive individuals. The genes involved assort independently of
each other.
© 2025 All rights reserved
, 4 | Page
Assume that a Chi-square test is provided a probability value of
0.02. Should the null hypothesis be accepted? Ans: No, when the
p value is <0.05, null hypothesis is rejected.
Albinism, lack of pigmentation in humans, results from an
autosomal recessive gene. Two parents with normal pigmentation
have an albino child. What is the probability that their next child
will be an albino girl? Ans: 1/4 X 1/2 = 1/8
A certain type of congenital deafness in humans is caused by a
rare autosomal dominant gene. If both parents are deaf
(heterozygous), would you expect all the children to be deaf?
Explain. Ans: No. In mating involving heterzygotes, three
genotypic classes are expected in the offspring: fully dominant,
fully recessive, and heterozygotes.
What conditions are likely to apply if the progeny from the cross
AaBb x AaBb appears in the 9:3:3:1 ratio? Ans: complete
dominance,
© 2025 All rights reserved
Genetics Questions and Correct Answers
T/F
Mendel's law of segregation is supported by a 1:1 testcross ratio.
Ans: True
T/F
The non-functional form of a gene is called a wild-type allele. Ans:
False
T/F
© 2025 All rights reserved
, 2 | Page
A gene can have maximum two alleles. Ans: False
T/F
To test Mendel's Law of Independent ASsortment, the
experimenter needs a minimum of two different genes and their
two alleles. Ans: True
T/F
A 1:1 phenotypic ratio is expected from a monohybrid testcross
with complete dominance Ans: True
What phenotypic ratios are likely to occur in crosses when dealing
with two completely dominant, independently segregating gene
pairs, when both parents are heterozygous? Ans: 9:3:3:1
© 2025 All rights reserved
, 3 | Page
Provide simple definitions that distinguish segregation and
independent assortment. Ans: Segregation is the separation of
alleles during meiosis, while independent assortment states that a
member of one gene pair has an equal and independent
opportunity of segregating with either member of another gene
pair.
In Chi-square analysis, what condition causes one to reject the
null-hypothesis? Ans: When the probability value is less than
0.05.
Assuming a typical monohybrid cross in which one allele is
completely dominant to the other, what ratio is expected if the
F1's are crossed? Ans: 3:1
Under what conditions does one expect a 1:1:1:1 ratio? Ans: in a
cross involving doubly heterozygous individuals crossed to fully
recessive individuals. The genes involved assort independently of
each other.
© 2025 All rights reserved
, 4 | Page
Assume that a Chi-square test is provided a probability value of
0.02. Should the null hypothesis be accepted? Ans: No, when the
p value is <0.05, null hypothesis is rejected.
Albinism, lack of pigmentation in humans, results from an
autosomal recessive gene. Two parents with normal pigmentation
have an albino child. What is the probability that their next child
will be an albino girl? Ans: 1/4 X 1/2 = 1/8
A certain type of congenital deafness in humans is caused by a
rare autosomal dominant gene. If both parents are deaf
(heterozygous), would you expect all the children to be deaf?
Explain. Ans: No. In mating involving heterzygotes, three
genotypic classes are expected in the offspring: fully dominant,
fully recessive, and heterozygotes.
What conditions are likely to apply if the progeny from the cross
AaBb x AaBb appears in the 9:3:3:1 ratio? Ans: complete
dominance,
© 2025 All rights reserved
