BIO 340 Exam 2 Questions And Answers With
Verified Solutions Graded A+ Latest Update 2025.
If black and white true-breeding mice are mated and the result is all gray offspring, what inheritance
pattern would this be indicative of? - ANSWER incomplete dominance
ABO blood groups are an example of: - ANSWER multiple alleles and codominance
Could an individual with blood type O (genotype ii) be a legitimate child of parents in which one parent
had blood type A and the other parent had blood type B? - ANSWER Yes, if each parent carries
one i allele
A white splashed (Bl/Bl) Andalausian chicken and a black (bl/bl) Andalusian chicken are crossed. The
heterozygotes produced show an intermediate phenotype (blue). What inheritance pattern would this be
indicative of? - ANSWER Incomplete dominance
A person with only one Sickle Cell Anemia allele and one unaffected allele will have some normal red
blood cells and some abnormal. What inheritance pattern would this be indicative of? - ANSWER
codominance
In a mating between two individuals that are heterozygous for a recessive lethal allele that is expressed in
utero, what genotypic ratio (homozygous dominant:heterozygous:homozygous recessive) would you
expect to observe in the offspring? - ANSWER 1:2:0
In rats, gene B produces black coat color if the genotype is B-, but black pigment is not produced if the
genotype is bb. At an independent locus, gene D produces yellow pigment if the genotype is D-, but no
pigment is produced when the genotype is dd. Production of both pigments results in brown coat color. If
neither pigment is produced, coat color is cream. The genotype of parents of litters with the following
phenotype distribution 3 brown, 3 yellow, 1 black, 1 cream is: - ANSWER BbDd x bbDd
In rats, gene B produces black coat color if the genotype is B-, but black pigment is not produced if the
genotype is bb. At an independent locus, gene D produces yellow pigment if the genotype is D-, but no
pigment is produced when the genotype is dd. Production of both pigments results in brown coat color. If
neither pigment is produced, coat color is cream. The phenotype of parents of litters with the following
phenotype distribution 3 brown, 3 yellow, 1 black, 1 cream is: - ANSWER brown and yellow
The wild-type coat color, agouti (AA) is dominant to solid-colored fur (aa). However, a separate gene C,
when present as the recessive homozygote (cc), negates any expression of pigment from the A gene and
results in an albino mouse. Therefore, the genotypes AAcc, Aacc, and aacc all produce the same albino
phenotype. A cross between heterozygotes for both genes (AaCc x AaCc) would generate offspring with a
phenotypic ratio of 9 agouti:3 black:4 albino. Which type of gene interaction is this? - ANSWER
Recessive epistasis.
Wild type blue-eyed Mary has blue flowers. Two genes control the pathway that makes the blue pigment:
The product of gene W turns a white precursor into magenta pigment. The product of gene M turns the
magenta pigment into blue pigment. Each gene has a recessive loss-of-function allele: w and m,
, respectively. A dihybrid (WwMm) is self-pollinated. What proportion of the offspring will be magenta? -
ANSWER 3/16
When genes are on different chromosomes, what percentage of gametes produced by a double
heterozygous individual will be recombinant? - ANSWER 50%
A species has n=4 chromosomes. Genes on the same chromosome have a maximum recombination
recombination rate of: - ANSWER 50%
A species has n=4 chromosomes. Genes on the same chromosome have a minimum recombination
recombination rate of: - ANSWER 0%
You are studying two linked genes that influence vine height and fruit color in squash. Yellow color is
dominant over green, and tall height is dominant over short. You get the following numbers of offspring
from your testcross: 198 Tall Yellow, 192 Short Green, 54 Tall Green, and 56 Short Yellow Which
offspring are recombinants? - ANSWER Tall Green and short yellow
You are studying two linked genes that influence vine height and fruit color in squash. Yellow color is
dominant over green, and tall height is dominant over short. You get the following numbers of offspring
from your testcross: 198 Tall Yellow, 192 Short Green, 54 Tall Green, and 56 Short Yellow What is the
distance between these genes? - ANSWER 22cM
You buy two sets of flowers from the same species, one set is only made of red flowers, while the other is
made of white flowers, and you know both sets were produced by only red and white parents,
respectively. Assume flower color is coded by a single autosomal gene. After crossing red flowers with
white flowers, all the offspring are banded red and white. What can you say about the alleles R and W of
the flower color gene? - ANSWER R and W are codominant
Huntington's disease is a rare neuro-degenerative disease which appears late in life and causes motor
function issues and dementia. The following pedigree shows the progression of the disease through a
family through multiple generations. What can you say about the genetic aspect of the disease? -
ANSWER It is caused by an autosomal dominant allele
The woman marked with a question mark is your friend. Knowing that you are taking Genetics, she
comes to ask you for advice: she wants to have children, but is afraid that they will be sick with the
disease. Her husband and her mother have no family history of HD. What is the probability that she is
sick? What is the probability that her children will be, without knowing her own status regarding the
disease? - ANSWER P(friend sick) = ½ ; P(child sick) = ¼
Your friend gets tested and the results are conclusive: she will not develop Huntington's disease. What is
the probability of her child having the disease now? - ANSWER 0
What is the relative genetic distance between two linked genes if the recombination frequency is 0.49? -
ANSWER 49cM
What statement best explains the distortion in Mendelian ratios observed by Bateson & Punnett in 1905?
(Reminder: they found an overrepresentation of F2 offspring showing both dominant or recessive
phenotypes, and an underrepresentation of offspring displaying one dominant and one recessive
phenotype). - ANSWER Gene linkage: Genes for flower color and pollen shape are physically
close on the same chromosome, leading to a breakdown in the independent assortment of the alleles for
these traits.
Verified Solutions Graded A+ Latest Update 2025.
If black and white true-breeding mice are mated and the result is all gray offspring, what inheritance
pattern would this be indicative of? - ANSWER incomplete dominance
ABO blood groups are an example of: - ANSWER multiple alleles and codominance
Could an individual with blood type O (genotype ii) be a legitimate child of parents in which one parent
had blood type A and the other parent had blood type B? - ANSWER Yes, if each parent carries
one i allele
A white splashed (Bl/Bl) Andalausian chicken and a black (bl/bl) Andalusian chicken are crossed. The
heterozygotes produced show an intermediate phenotype (blue). What inheritance pattern would this be
indicative of? - ANSWER Incomplete dominance
A person with only one Sickle Cell Anemia allele and one unaffected allele will have some normal red
blood cells and some abnormal. What inheritance pattern would this be indicative of? - ANSWER
codominance
In a mating between two individuals that are heterozygous for a recessive lethal allele that is expressed in
utero, what genotypic ratio (homozygous dominant:heterozygous:homozygous recessive) would you
expect to observe in the offspring? - ANSWER 1:2:0
In rats, gene B produces black coat color if the genotype is B-, but black pigment is not produced if the
genotype is bb. At an independent locus, gene D produces yellow pigment if the genotype is D-, but no
pigment is produced when the genotype is dd. Production of both pigments results in brown coat color. If
neither pigment is produced, coat color is cream. The genotype of parents of litters with the following
phenotype distribution 3 brown, 3 yellow, 1 black, 1 cream is: - ANSWER BbDd x bbDd
In rats, gene B produces black coat color if the genotype is B-, but black pigment is not produced if the
genotype is bb. At an independent locus, gene D produces yellow pigment if the genotype is D-, but no
pigment is produced when the genotype is dd. Production of both pigments results in brown coat color. If
neither pigment is produced, coat color is cream. The phenotype of parents of litters with the following
phenotype distribution 3 brown, 3 yellow, 1 black, 1 cream is: - ANSWER brown and yellow
The wild-type coat color, agouti (AA) is dominant to solid-colored fur (aa). However, a separate gene C,
when present as the recessive homozygote (cc), negates any expression of pigment from the A gene and
results in an albino mouse. Therefore, the genotypes AAcc, Aacc, and aacc all produce the same albino
phenotype. A cross between heterozygotes for both genes (AaCc x AaCc) would generate offspring with a
phenotypic ratio of 9 agouti:3 black:4 albino. Which type of gene interaction is this? - ANSWER
Recessive epistasis.
Wild type blue-eyed Mary has blue flowers. Two genes control the pathway that makes the blue pigment:
The product of gene W turns a white precursor into magenta pigment. The product of gene M turns the
magenta pigment into blue pigment. Each gene has a recessive loss-of-function allele: w and m,
, respectively. A dihybrid (WwMm) is self-pollinated. What proportion of the offspring will be magenta? -
ANSWER 3/16
When genes are on different chromosomes, what percentage of gametes produced by a double
heterozygous individual will be recombinant? - ANSWER 50%
A species has n=4 chromosomes. Genes on the same chromosome have a maximum recombination
recombination rate of: - ANSWER 50%
A species has n=4 chromosomes. Genes on the same chromosome have a minimum recombination
recombination rate of: - ANSWER 0%
You are studying two linked genes that influence vine height and fruit color in squash. Yellow color is
dominant over green, and tall height is dominant over short. You get the following numbers of offspring
from your testcross: 198 Tall Yellow, 192 Short Green, 54 Tall Green, and 56 Short Yellow Which
offspring are recombinants? - ANSWER Tall Green and short yellow
You are studying two linked genes that influence vine height and fruit color in squash. Yellow color is
dominant over green, and tall height is dominant over short. You get the following numbers of offspring
from your testcross: 198 Tall Yellow, 192 Short Green, 54 Tall Green, and 56 Short Yellow What is the
distance between these genes? - ANSWER 22cM
You buy two sets of flowers from the same species, one set is only made of red flowers, while the other is
made of white flowers, and you know both sets were produced by only red and white parents,
respectively. Assume flower color is coded by a single autosomal gene. After crossing red flowers with
white flowers, all the offspring are banded red and white. What can you say about the alleles R and W of
the flower color gene? - ANSWER R and W are codominant
Huntington's disease is a rare neuro-degenerative disease which appears late in life and causes motor
function issues and dementia. The following pedigree shows the progression of the disease through a
family through multiple generations. What can you say about the genetic aspect of the disease? -
ANSWER It is caused by an autosomal dominant allele
The woman marked with a question mark is your friend. Knowing that you are taking Genetics, she
comes to ask you for advice: she wants to have children, but is afraid that they will be sick with the
disease. Her husband and her mother have no family history of HD. What is the probability that she is
sick? What is the probability that her children will be, without knowing her own status regarding the
disease? - ANSWER P(friend sick) = ½ ; P(child sick) = ¼
Your friend gets tested and the results are conclusive: she will not develop Huntington's disease. What is
the probability of her child having the disease now? - ANSWER 0
What is the relative genetic distance between two linked genes if the recombination frequency is 0.49? -
ANSWER 49cM
What statement best explains the distortion in Mendelian ratios observed by Bateson & Punnett in 1905?
(Reminder: they found an overrepresentation of F2 offspring showing both dominant or recessive
phenotypes, and an underrepresentation of offspring displaying one dominant and one recessive
phenotype). - ANSWER Gene linkage: Genes for flower color and pollen shape are physically
close on the same chromosome, leading to a breakdown in the independent assortment of the alleles for
these traits.
