WGU C652 Final Exam (Latest 2024/ 2025 Update)
Genetics and Heredity| Prep Questions and Verified
Answers| 100% Correct| Grade A
T/F
Mendel's law of segregation is supported by a 1:1 testcross ratio. - ANSWERTrue
T/F
The non-functional form of a gene is called a wild-type allele. - ANSWERFalse
T/F
A gene can have maximum two alleles. - ANSWERFalse
T/F
To test Mendel's Law of Independent ASsortment, the experimenter needs a
minimum of two different genes and their two alleles. - ANSWERTrue
T/F
A 1:1 phenotypic ratio is expected from a monohybrid testcross with complete
dominance - ANSWERTrue
What phenotypic ratios are likely to occur in crosses when dealing with two
completely dominant, independently segregating gene pairs, when both parents are
heterozygous? - ANSWER9:3:3:1
Provide simple definitions that distinguish segregation and independent assortment.
- ANSWERSegregation 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? -
ANSWERWhen 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? - ANSWER3:1
Under what conditions does one expect a 1:1:1:1 ratio? - ANSWERin a cross involving
doubly heterozygous individuals crossed to fully recessive individuals. The genes
involved assort independently of each other.
,Assume that a Chi-square test is provided a probability value of 0.02. Should the null
hypothesis be accepted? - ANSWERNo, 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? - ANSWER1/4 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. - ANSWERNo. 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? - ANSWERcomplete dominance,
independent assortment,
no gene interaction
What happens in a chi-square test, if the value of X^2 increases? - ANSWERthe
likelihood of rejecting the null hypothesis increases
In peas, gray seed color is dominant to white. For the purpose of these questions
assume that Mendel crossed plants with gray seeds with each other and the
following progeny were produced: 250 gray and 80 white.
A) What is the most probable genotype of each parent?
B) What genotypic and phenotypic ratios are expected in the progeny of such a
cross? - ANSWERA) Gg and Gg (G=gray, g=white)
B) Genotypic= 1:2:1
Phenotypic= 3:1
The phenotype for vestigial wings (vg) in Drosophila is caused by a recessive mutant
gene that independently assorts with a recessive gene for hairy (h) body. Assume
that a cross is made between a fly with normal wings and a hairy body AND a fly with
vestigial wings and a normal body hair. The wild type F1 flies were crossed among
each other to produce 1024 offspring. What phenotype would you expect among the
1024 offspring and how many of each phenotype would you expect? -
ANSWERPhenotypes: Wild, vestigial, hair, vestigial hairy
Numbers Expected: {9:3:3:1}: wild (576), vestigial (192), hairy (192), vestigial hairy
(64)
in a family of seven children, what is the probability of obtaining the following
number of boys and girls?
A) all boys
B) All children of the same sex
C) Six girls and one boy
D) Four boys and three girls
,E) Four girls and three boys - ANSWERA) (1/2)^7 = 1/128
B) (1/2)^7 chance of being all boys and (1/2)^7 chance of being all girls. 1/128 +
1/128 = 1/64
C)7/128
D) 35/128
E) 35/128
Alkaptonuria is a metabolic disorder which results from an allele (a) that is recessive
to the allele for the normal gene (A). Sally has normal metabolism, but her brother
and father have Alkaptonuria, and her mother has normal metabolism.
A) Give the genotypes of Sally, her mother, father, and her brother.
B) If Sally's parents have another child, what is the probability that this child will
have Alkaptonuria?
C) If Sally marries a man with Alkaptonuria, what is the probability that their first
child will have this metabolic disorder? - ANSWERA) Sally (Aa), Mother (Aa), Father
(aa), and brother (aa)
B) 1/2
C) 1/2
The following two genotypes are crossed: Aa Bb Cc dd Ee and Aa bb Cc Dd Ee. What
will the proportion of the following genotypes be among the progeny of this cross?
A) Aa Bb Cc Dd Ee
B) Aa bb Cc dd ee
C) Aa bb cc dd ee
D) AA DD CC DD EE - ANSWERA) 1/2 Aa x 1/2 Bb x 1/2 Cc x 1/2 Dd x 1/2 Ee = 1/32
B) 1/2 Aa x 1/2 bb x 1/2 Cc x 1/2 dd x 1/4 ee = 1/64
C) 1/4 aa x 1/2 bb x 1/4 cc x 1/2 dd x 1/4 ee = 1/256
D) no offspring with this genotype. The AaBbCcddEe parent can not provide a D and
the other parent can not contribute a B allele.
, A recessive allele in tigers causes the white tiger. If two normally pigmented tigers
are mated and produce a white offspring, what percentage of their remaining
offspring would be expected to have NORMAL pigmentation? - ANSWER75%
Polydactyly is expressed when an individual has extra fingers/toes. Having extra
digits is caused by a dominant allele. If a man with polydactyly marries a woman with
normal number of digits and has one son with normal hands and feet and one with
extra digits, what is the probability that their next child will have polydactyly? -
ANSWER1/2
Tightly curled hair is caused by a dominant gene in humans. If a heterozygous curly-
haired person marries a person with straight hair; what fraction of their offspring
would be expected to have straight hair? - ANSWER1/2 straight
What type of genotypic and phenotypic ratios are likely to occur in crosses when
dealing with a single gene pair where all the genotypic combinations are of equal
viability? - ANSWERgenotypic=1:2:1
phenotypic=3:1
Assume that a black guinea pig crossed with an albino guinea pig produced five black
offspring. When the albino was crossed with a second black one, 4 black and 3 albino
offspring were produced. What genetic explanation would apply to these data? -
ANSWERAlbino= recessive, black= dominant
The fundamental Mendelian process that involves the separation of contrasting
genetic elements at the same locus would be called..? - ANSWERSegregation
The chi-square test involves a statistical comparison between observed and expected
values. One generally determines degrees of freedom as..? - ANSWEROne less the
number of classes being compared
With incomplete dominance, a likely ratio resulting from a monohybrid cross would
be - ANSWER1:2:1
A condition in which one gene pair masks the expression of a nonallelic gene pair is
called - ANSWEREpistasis
Hemizygosity would most likely be associated with which of the following? -
ANSWERX-linked inheritance
In a mating between individuals with the genotypes IAIB X IOIO, what percentage of
the offspring is expected to have the O blood type? - ANSWER0
If an X-linked disorder is lethal to the affected individual prior to the age at which
one attains reproductive maturity, the lethality will be expressed in males only. This
Genetics and Heredity| Prep Questions and Verified
Answers| 100% Correct| Grade A
T/F
Mendel's law of segregation is supported by a 1:1 testcross ratio. - ANSWERTrue
T/F
The non-functional form of a gene is called a wild-type allele. - ANSWERFalse
T/F
A gene can have maximum two alleles. - ANSWERFalse
T/F
To test Mendel's Law of Independent ASsortment, the experimenter needs a
minimum of two different genes and their two alleles. - ANSWERTrue
T/F
A 1:1 phenotypic ratio is expected from a monohybrid testcross with complete
dominance - ANSWERTrue
What phenotypic ratios are likely to occur in crosses when dealing with two
completely dominant, independently segregating gene pairs, when both parents are
heterozygous? - ANSWER9:3:3:1
Provide simple definitions that distinguish segregation and independent assortment.
- ANSWERSegregation 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? -
ANSWERWhen 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? - ANSWER3:1
Under what conditions does one expect a 1:1:1:1 ratio? - ANSWERin a cross involving
doubly heterozygous individuals crossed to fully recessive individuals. The genes
involved assort independently of each other.
,Assume that a Chi-square test is provided a probability value of 0.02. Should the null
hypothesis be accepted? - ANSWERNo, 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? - ANSWER1/4 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. - ANSWERNo. 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? - ANSWERcomplete dominance,
independent assortment,
no gene interaction
What happens in a chi-square test, if the value of X^2 increases? - ANSWERthe
likelihood of rejecting the null hypothesis increases
In peas, gray seed color is dominant to white. For the purpose of these questions
assume that Mendel crossed plants with gray seeds with each other and the
following progeny were produced: 250 gray and 80 white.
A) What is the most probable genotype of each parent?
B) What genotypic and phenotypic ratios are expected in the progeny of such a
cross? - ANSWERA) Gg and Gg (G=gray, g=white)
B) Genotypic= 1:2:1
Phenotypic= 3:1
The phenotype for vestigial wings (vg) in Drosophila is caused by a recessive mutant
gene that independently assorts with a recessive gene for hairy (h) body. Assume
that a cross is made between a fly with normal wings and a hairy body AND a fly with
vestigial wings and a normal body hair. The wild type F1 flies were crossed among
each other to produce 1024 offspring. What phenotype would you expect among the
1024 offspring and how many of each phenotype would you expect? -
ANSWERPhenotypes: Wild, vestigial, hair, vestigial hairy
Numbers Expected: {9:3:3:1}: wild (576), vestigial (192), hairy (192), vestigial hairy
(64)
in a family of seven children, what is the probability of obtaining the following
number of boys and girls?
A) all boys
B) All children of the same sex
C) Six girls and one boy
D) Four boys and three girls
,E) Four girls and three boys - ANSWERA) (1/2)^7 = 1/128
B) (1/2)^7 chance of being all boys and (1/2)^7 chance of being all girls. 1/128 +
1/128 = 1/64
C)7/128
D) 35/128
E) 35/128
Alkaptonuria is a metabolic disorder which results from an allele (a) that is recessive
to the allele for the normal gene (A). Sally has normal metabolism, but her brother
and father have Alkaptonuria, and her mother has normal metabolism.
A) Give the genotypes of Sally, her mother, father, and her brother.
B) If Sally's parents have another child, what is the probability that this child will
have Alkaptonuria?
C) If Sally marries a man with Alkaptonuria, what is the probability that their first
child will have this metabolic disorder? - ANSWERA) Sally (Aa), Mother (Aa), Father
(aa), and brother (aa)
B) 1/2
C) 1/2
The following two genotypes are crossed: Aa Bb Cc dd Ee and Aa bb Cc Dd Ee. What
will the proportion of the following genotypes be among the progeny of this cross?
A) Aa Bb Cc Dd Ee
B) Aa bb Cc dd ee
C) Aa bb cc dd ee
D) AA DD CC DD EE - ANSWERA) 1/2 Aa x 1/2 Bb x 1/2 Cc x 1/2 Dd x 1/2 Ee = 1/32
B) 1/2 Aa x 1/2 bb x 1/2 Cc x 1/2 dd x 1/4 ee = 1/64
C) 1/4 aa x 1/2 bb x 1/4 cc x 1/2 dd x 1/4 ee = 1/256
D) no offspring with this genotype. The AaBbCcddEe parent can not provide a D and
the other parent can not contribute a B allele.
, A recessive allele in tigers causes the white tiger. If two normally pigmented tigers
are mated and produce a white offspring, what percentage of their remaining
offspring would be expected to have NORMAL pigmentation? - ANSWER75%
Polydactyly is expressed when an individual has extra fingers/toes. Having extra
digits is caused by a dominant allele. If a man with polydactyly marries a woman with
normal number of digits and has one son with normal hands and feet and one with
extra digits, what is the probability that their next child will have polydactyly? -
ANSWER1/2
Tightly curled hair is caused by a dominant gene in humans. If a heterozygous curly-
haired person marries a person with straight hair; what fraction of their offspring
would be expected to have straight hair? - ANSWER1/2 straight
What type of genotypic and phenotypic ratios are likely to occur in crosses when
dealing with a single gene pair where all the genotypic combinations are of equal
viability? - ANSWERgenotypic=1:2:1
phenotypic=3:1
Assume that a black guinea pig crossed with an albino guinea pig produced five black
offspring. When the albino was crossed with a second black one, 4 black and 3 albino
offspring were produced. What genetic explanation would apply to these data? -
ANSWERAlbino= recessive, black= dominant
The fundamental Mendelian process that involves the separation of contrasting
genetic elements at the same locus would be called..? - ANSWERSegregation
The chi-square test involves a statistical comparison between observed and expected
values. One generally determines degrees of freedom as..? - ANSWEROne less the
number of classes being compared
With incomplete dominance, a likely ratio resulting from a monohybrid cross would
be - ANSWER1:2:1
A condition in which one gene pair masks the expression of a nonallelic gene pair is
called - ANSWEREpistasis
Hemizygosity would most likely be associated with which of the following? -
ANSWERX-linked inheritance
In a mating between individuals with the genotypes IAIB X IOIO, what percentage of
the offspring is expected to have the O blood type? - ANSWER0
If an X-linked disorder is lethal to the affected individual prior to the age at which
one attains reproductive maturity, the lethality will be expressed in males only. This
