X & Y Chromosomes
This is the method in mammals that keeps the levels of expression of the genes on the X-chromosome similar in both sexes.
X-Chromosome Inactivation
Which of the following is true about two genes calculated to be 23 cM apart?
A. The two genes are linked and are more likely to travel together than cross over.
B. There is a 77% recombinant frequency.
C. The recombinant F2 offspring would be equally likely as the parental F2 offspring.
D. All of the above are true
A. The two genes are linked and are more likely to travel together than cross over.
Which of the following is false about the missing heritability of height in humans discussed in the lecture?
A. A genome-wide association study in 2022 found an estimated 50% heritability.
B. The study's weakness was the lack of geographic and ethnic diversity.
C. The researchers found 12,111 genetic variants associated with height.
D. The earlier genome-wide association studies before this one found an estimated 80% heritability for height in humans.
D. The earlier genome-wide association studies before this one found an estimated 80% heritability for height in humans.
Blood type depends on the absence or presence of certain proteins on the surface of red blood cells, not related to each other. For example, a person with B blood type has just B proteins while a person with AB blood type has both A & B proteins. What phenomenon is this?
Codominance
Two cloned rabbits with identical genomes are placed in two different environments: one in a tundra and the other in a forest. After many months of the rabbit's lives, the one in the tundra develops a long, white fur coat, while the one in the forest retains a short, brown fur coat. What is this displaying?
A. Canalization of fur coat length & color
B. Phenotypic plasticity of fur coat length & color
C. Maternal impriniting
D. Parternal
B. Phenotypic plasticity of fur coat length & color
Using the pedigree provided, what is the chance of individuals IV-2 & IV-3 having an affected son?
50% or 1/2
If there are 2000 individuals produced in F2 generation and the two genes were not linked and followed Mendel's laws perfectly, how many recombinant and parental offspring would there be?
1,000 parental & 1,000 recombinant
The broad sense heritability of whisker length in cats is 0.35. Which of the following is true?
A. 0.35 represents the fraction of variation in whisker length due to genetics.
B. 0.35 represents the fraction of variation in whisker length due to the environment.
C. 0.35 represents the fraction of variation in whisker length due to both genetics and environment.
D. 0.35 represents the variation in genetics of whisker length.
A. 0.35 represents the fraction of variation in whisker length due to genetics.
Flowers express a certain color based on the activity of certain genes. Purple flowers are more likely to be pollinated. The R genomic locus creates a red color while the B genomic locus creates a blue color. If a purple flower is more likely to get pollinated than a blue or red flower, what is this showing?
A. Epistasis
B. Additive alleles
C. Codominance
D. Epigenetics
B. Additive alleles
Which of the following is true about epigenetics?
A. The bases G & T can be methylated.
B. The enzymes DAMM methylases can add or remove methyl groups.
C. Methylated DNA tends to be in euchromatin.
D. The genome constantly stays in either euchromatin or heterochromatin.
E. All are true
B. The enzymes DAMM methylases can add or remove methyl groups.
Which of the following is false about X-inactivation?
A. The Xist transcripts coat the X destined to be inactivated and silence it.
B. The X-inactivation center contains the Xist genomic which codes for an RNA molecule.
C. The Xist RNA molecules methylate the entire X-chromosome that is silenced to become the Barr body.
D. This process is random when deciding which X chromosome is inactivated.
C. The Xist protein molecules methylate the entire X-chromosome that is silenced to become the Barr body.
The parents with the genotypes AABB & aabb are crossed. Their F1 offspring are test crossed and you receive the following data. Calculate the map distance between A & b genomic loci.
AaBb - 500
Aabb - 32
aaBb - 35
aabb - 495
6.30 cM
Use the following data to calculate the broad sense heritability: VE = 110, VA = 77, and VD = 52.
H2 = 0.54
A base change in the trans sequence of the Ras gene results in the amino acid valine instead of glycine. Ras usually promotes cell growth and proliferation and is turned off when unneeded. In cancer cells, it tends to be continuously active. Which of the following is true?
A. A GOF mutation in a pleiotropic gene
B. A LOF mutation in a pleiotropic gene
C. A nonsynonymous mutation
D. A & C
E. B & C
D. A & C
The F genomic locus that codes for feather color in owls is expressed differently depending on the environment. If the F genomic locus is expressed, the F protein results in the brown-speckled color of owls. Owls that live in cold environments do not express this protein in their feathers. Which of the following is true?
A. Winter owls have the F genomic locus in euchromatin.
B. Winter owls have the F genomic locus in heterochromatin.
C. Winter owl cells have a methylated F genomic locus.
D. B & C
E. A & C
D. B & C
Using the pedigree provided showing a family history of hemophilia, what must be the genotypes of III-2 & IV-2?
XHXh or Carriers fro hemophilia
Two true-breeding parents were crossed (RTRT & rtrt). Their F1 offspring are test crossed to produce 1500 F2 offspring. If the map distance between R & T is 13 cM, how many individuals are recombinant and parental?
195 recombinant & 1,305 parental
In a Colomesus asellus (pufferfish) population, the mean number of spines is 302. From this population, a group was chosen (selected) which had an average spine number of 311. The offspring of the chosen group had an average of 305 spines. Calculate the narrow-sense heritability of spines in pufferfish.
h2=0.33
Coat color in labrador retriever dog breed depends on two genomic loci: E & B. If dogs have EE or Ee, they will be either chocolate or black depending on the B locus. If they have ee, they will be golden no matter what the B allele is. This is an example of what?
A. Epistasis
B. Additive alleles
C. Codominance
D. Genetic linkage
A. Epistasis
Angelman syndrome is caused by a lack of expression of the gene UBE3A on chromosome 15 during development. This occurs when the affected individual inherits both copies of this gene from their father. Which of the following is true?
A. This gene is maternally imprinted, and thus the individual inherits two methylated UBE3A alleles.
B. This gene is paternally imprinted, and thus the individual inherits two unmethylated UBE3A alleles.
C. This gene is paternally imprinted, and thus the individual inherits two methylated UBE3A alleles.
D. This gene is maternally imprinted, and thus the individual inherits two unmethylated UBE3A alleles.
C. This gene is paternally imprinted, and thus the individual inherits two methylated UBE3A alleles.
Use the provided karyotype to determine what is true. The individual is phenotypically female with this karyotype.
A. The SRY gene has a frameshift mutation
B. One X chromosome is inactivated
C. The SRY gene is duplicated
D. The Xist gene has a nonsense mutation in both X-chromosomes
A. The SRY gene has a frameshift mutation
In stickleback fish, three genes (N, T, H) are linked.
A true-breeding stickleback (NNttHH) is crossed to another true-breeding stickleback (nnTThh). Their F1 offspring is test crossed. Using the data from the F2 offspring to find the gene in the middle.
NtH - 2129
ntH - 159
NTH - 260
nth - 270
NTh - 163
nTh - 2150
Nth - 10
nTH - 30
The H genomic locus is in the middle
The Kirschner lab wants to make larger butterflies. They started with a random-bred population of butterflies with an average wingspan of 6 cm. They chose a group with an average wingspan of 8.1 cm to be the next generation's parents. They determined that VE = 1320, VA = 850, and VD = 400. What is the average wingspan of the next generation?
6.7 cm
The quality of racing dogs depends on some genetic input. This is due to there being many QTLs for running speed. The gene S and gene D are two of them. Gene S codes for a protein that allows for more oxygen input and allows for gene D to be expressed more. Gene D codes for a protein that improves muscle repairing. Which is true?
A. Gene S and gene D are synergistic
B. Gene S and gene D are antagonistic
C. Gene S exibits pleiotropy
D. Both A & C
E. Both B & C
D. Both A & C
A young female honey bee is exposed to the high nutrition of royal jelly during development, and the genes allowing for the bee to develop into a queen bee are expressed. If the female honey bee is exposed to low nutrition, and not much royal jelly during development, the bee does not express queen bee traits, they can not reproduce and become worker bees. For worker bees (female, non-queen) what is occurring to the queen bee genes and what type of chromatin are they in?
The queen bee genes are being methylated and the gens are in heterochromatin