Seven Lakes Invitational — Designer Genes

If two mutant organisms produce 12 offspring, which of the following resulting phenotypes would prove complementation?

A man heterozygous for polydactyly (Aa) marries a woman who also has polydactyly. They produce 5 children, 2 of which have polydactyly. Polydactyly has 90% penetrance. What is the probability that the woman is heterozygous (Aa)?

A pumpkin plant heterozygous for both orange pigment (orange is dominant, white is recessive) and warts (warts are dominant, no warts are recessive) is crossed with a pumpkin recessive for both traits. If the recombination frequency is 18%, how many of the 700 offspring will possess parental alleles?

If the RF in the last question was 50% what could this indicate about the gene controlling orange pigment and the gene controlling warts? Select all that apply.

In a species of fish, the gene C controls scale color (C=colored, c=albino) and gene M controls fin length (M=long, m=short). 2 fish heterozygous for both traits are crossed, but a continuous range of fin lengths is observed in their offspring. Which of the following statements is correct regarding the offsprings’ phenotypic ratio?

In a family, the mother has type A blood and the father has type O blood. If their first three children have type A blood, what is the probability that their fourth child will have type O blood?

Why did Gregor Mendel use Pisum Satvium as his plant for experimentation? Select all that apply.

If a cell is unable to exit the cell cycle, which of the following has likely been inhibited?

Which of the following statements about the interaction between cyclins and CDKs is false?

Given that a drug inhibits cohesin cleavage, which stage of mitosis would be directly prevented?

Which checkpoint ensures that all chromosomes are properly attached to spindle fibers before anaphase starts?

In a cell that you see that is currently undergoing division, you do a Western Blot assay and see that there is a dark, thick band that corresponds to SYCP1 (a synaptonemal complex protein). You see that SYCP1 starts to disassemble. In what stage of division is the cell?

Turner Syndrome occurs when a female individual has only one X chromosome. This condition can arise from nondisjunction in either parent, producing a gamete with no sex chromosome. In which of the following stages could nondisjunction have occurred to produce such gamete? Select all that apply.

What checkpoint is primarily responsible for preventing a cell with damaged or incompletely replicated DNA from entering mitosis?

A study on the effects of a chemical known as CPT is being conducted. Results of flow cytometry are depicted on the image sheet alongside gel electrophoresis of DNA content of the control group and CPT-treated cells. Select all statements that are likely true.

A mad scientist decides to modify a Cdk that phosphorylates both ORC and MCM helicase during S phase, which inactivates ORC and activates MCM helicase. Select all statements that are likely to be true in a cell with a modified version of this Cdk.

Which of the following syndromes results in a small jaw and what type of aneuploidy is it?

Fill in the blank: Down syndrome is also known as trisomy ____, which would be notated as ____ for a male individual.

A biologist decides to modify a B cell with one mutated allele that alters the structure of IgA antibodies using a genetic marker placed next to the mutant locus. To his surprise, upon activation within the body of the mouse he was testing on, daughter cells were found with wild-type alleles on the same chromosome as the marker. How can this be explained?

Which of the following syndrome results in a Cleft lip and what type of aneuploidy is it?

During prophase, a human cell undergoing mitosis has. . .

In a population of 1200 Magikarp, 300 out of 600 males have the X-linked recessive skelly trait. Assuming the population is under Hardy-Weinberg equilibrium, what is the probability of a random female Magikarp having a baby expressing the skelly trait if she mates with one of the males that expresses the trait?

As one increases the resolution of a phylogeny deeper into lower levels of classification, defining ____ can become less-useful ____.

Given the phylogenetic tree on the image sheet, maximum parsimony would assume how many mutations? In this diagram, only charophytes, chytrids, and animals possess centrioles in their life cycles. Assume a mutation can only add or remove expression of centrioles. (For the purposes of this question, assume the Chytrids are a clade even though they are polyphyletic in real life).

A phylogeneticist wishes to demonstrate the effects of long-branch attraction using a computer model. In the above graph, l1 represents the length of the human and rat branches while l2 represents the length of the chimp and mouse branches. The y-axis graphs frequencies of sites that match between the species pairs. Given that the unrooted trees depict "true" phylogenies in their topology, select all of the conclusions that can be drawn from this.

The height in a certain species of plant varies from 50 cm to 100 cm and is equally influenced by 5 loci. If 2 plants heterozygous for all 5 loci are bred, what is the expected proportion of plants that will have a height of at least 75 cm?

During meiosis, homologous chromosomes undergo crossing over. Which of the following statements accurately describes the molecular basis and evolutionary significance of this process?

A population of lizards experiences a sudden catastrophic environmental event that drastically reduces its population size and randomly eliminates certain alleles. Which evolutionary concept best describes this phenomenon, and what are the likely long-term genetic consequences?

Select the scenario with the highest fixation index:

XP may be a silly emoticon, but it also stands for xenoderma pigmentosum, a genetic disease in which individuals are highly photosensitive and vulnerable to skin cancer. Which DNA repair mechanism is likely impaired here?

In photosynthetic organisms, which additional DNA repair mechanism is also used to reduce photosensitivity even further?

Although it is a method of DNA repair, BER actually produces an intermediate stage mirroring a particular phenomenon causing mutation. What phenomenon is this?

In a lab, scientists are testing the effects of fluoroquinolones in an experiment in which relaxed DNA was incubated with DNA gyrase and fluoroquinolones to produce the gel electrophoresis results on the image sheet. These drugs are known to inhibit DNA gyrase and topoisomerase IV. Select all of the following true statements regarding this scenario.

Which enzyme is responsible for replacing RNA primers with DNA?

Doctor Darjav loves Tautomer Shifts. Specifically, he analyzes DNA sequences from Sarah, and is looking for mutations that can result from spontaneous base pair changes. Which of the following base pairs are mismatched and result from the imino form of Cytosine?

Heterochromatin plays a role in things like gene silencing and chromosome stability. Which of the following is it most typically associated with?

A point mutation occurs in the coding sequence of a eukaryotic gene. The original codon was 5’-AAA-3’, encoding for lysine. After the mutation occurred, the codon was altered to 5’-AAG-3’, which also encodes for lysine. However, cells that express this mutated gene show significantly reduced protein levels, despite no changes in mRNA abundance. Which of the following best explains this observation?

A point mutation occurs at the last nucleotide of an exon immediately adjacent to the 5’ splice site of an intron. Which of the following is the most likely effect on the resulting mRNA and protein?

Adding bases to the 5’ end is illegal and also detrimental to the fidelity of DNA polymerase. Which of the following best explains why that is?

What is the difference between acetylation and methylation of histones?

Which subunit of the DNA Polymerase III Holoenzyme is responsible for proofreading?

A researcher is examining the combined effect of a mutation in a DNA repair enzyme and exposure to a chemical mutagen that causes bulky adducts. The repair enzyme normally functions in base excision repair (BER). Which outcome is most likely to be observed in this system?

A constitutive mutation in the lacI gene causes continuous expression of the lac operon, even in the absence of lactose. Which type of mutation is responsible for this phenotype, and why?

Consecutive pyrimidines in DNA can form covalent dimers when exposed to ultraviolet radiation, disrupting replication. A type of DNA repair called direct reversal fixes these lesions in some organisms. Which specific process (that humans lack) repairs these UV-induced dimers, and which enzyme carries it out?

Select all of the following statements that are FALSE:

In prokaryotes, what does the -10 region have in common with rho-independent termination?

Believe it or not, many cancers actually take advantage of the body's own mechanism of reverse transcription. How is it used to their advantage?

The trp operon possesses negative regulation by attenuation, in which stalling of a ribosome upon a leader peptide prevents the formation of a termination loop when tryptophan is scarce. Select all of the scenarios in which trp operon transcription would be completed assuming attenuation is the only form of regulation.

Which of the following template strand sequences would be most likely to result in rho-independent transcription termination?

Positive control is dictated by ____ while negative control is dictated by ____, both of which are ____.

In a cell that is using a growth medium that contains lactose, you see that it's pH substantially decreases. What gene is being overexpressed?

What regions of mRNA in the trp operon will prevent attenuation when hydrogen bonded together?

Which of the following reasons is why mutation rates are much faster in non-essential DNA compared to essential DNA?

What operator(s) in the lac operon is most important for negative control of gene expression?

Which molecule acts as an inducer by binding to the lac repressor and inactivating it, allowing transcription of the lac operon?

A mutation occurs in a transcription factor gene that encodes a protein which normally activates multiple genes in the cell. Which type of regulatory effect is most likely impacted?

A mutation changes the sequence of the TATA box in a eukaryotic gene from TATAA to TCGGAA. What is the most likely effect on transcription of this gene?

Which of the following best describes the flow of genetic information in most cells, according to the Central Dogma?

The Shine-Dalgarno Sequence aligns mRNA with...

A cell biologist is using ChIP to study the H3K9me3 modification of histones. Select all of the following statements that are true about this analysis.

This same cell biologist continues his study of histones by attempting to inactivate a core histone gene using CRISPR-Cas9 to create a deletion by NHEJ. However, he finds that his results demonstrate an unusual number of seemingly healthy cells, with many actively dividing, but also some in G0. What might have led to this? Select all that apply.

Which of the following correctly pairs a sequencing method with its limitation? Select all that apply.

Cells under certain physiological conditions can process endogenous RNA hairpin transcripts into around 7-nucleotide single-stranded fragments that are loaded into protein complexes. These short RNAs bind partially complementary sites on target mRNAs, leading to reversible inhibition of translation without mRNA degradation. Which statement correctly characterizes this process?

Which of the following is a fundamental advantage of third-generation sequencing over next-generation sequencing when resolving highly repetitive genomic regions?

In Sanger sequencing, which of the following features is directly responsible for terminating DNA strand elongation during the chain-terminal reaction?

During PCR, which step’s temperature is most critical for determining the specificity of primer binding, and what is the primary molecular reason for this dependence?

A researcher is using CRISPR-Cas 9 to knock out a gene in yeast. They design a guide RNA that matches a 20-base sequence in exon 2 of the gene. However, Cas9 only cuts when the target sequence is next to a specific 3-base motif in the genome. What feature allows Cas9 to correctly recognize and cut the target DNA?

Scientists are attempting to create a recombinant colony of bacteria with a gene that encodes for methicillin resistance. They place bacteria with potential recombinant vectors in a blue-white screen and blue and white colonies are formed. Which color is a resistant colony most likely to be?

What is the correct order of steps in a typical PCR cycle?

Illumina sequencing detects incorporated nucleotides using which of the following?

A common molecular cloning technique is Gibson assembly, where DNA fragments are joined without the use of restriction enzymes. This method relies on enzymes to create complementary single stranded overhangs, fill missing nucleotides, and seal the backbone. Fragments are joined using the combined activity of what?

CRISPR-Cas9 is used to create knockouts in specific genes. Which type of mutation typically results when the DNA is repaired by non-homologous end joining?

John’s hamster is sick, and he (John, not the hamster) wants to conduct a PCR to test for the bacteria in his (the hamster’s, not John’s) GI tract. However, there’s many types of PCR, and John, besides not knowing the differences between the procedures, doesn’t even know what bacterial strain he’s looking for! What type of PCR should John conduct?

Assuming simple Mendelian patterns of dominance, a male brown moth is crossed with a female gray moth to produce all brown female offspring and all gray male offspring. These moths have Z-W sex determination and the coloration gene is Z-linked. A female from the F1 generation is crossed with a gray male moth from a foreign strain of wild moths. The first 4 offspring are 3 gray males followed by 1 gray female. To the nearest whole percentage, the probability that the next offspring is brown is ____%. Show all work.

What phenomenon is being observed by the researchers (include dominant or recessive)?

An organism with genotype Aabb is crossed with another organism with genotype aaBb. What is the expected phenotype ratio?

In a related species with the same inheritance pattern, genes A and B are linked at 25 cM. If the same initial crosses are run, what percentage of organisms in the F2 generation will have a black coat color? Round to the nearest whole number.

What kind of chromosomal abnormality was detected by the karyotype on the image sheet? Which 2 chromosomes are involved?

What is the realized heritability for this trait?

If 85% of variance due to genetics in this trait is caused by additive effects, what is the broad-sense heritability for this trait?

What is the expected average presents carried for the offspring population if instead Dr. Sillbun selects 2 Grinches from the original population who only carry 17 presents?

A phylogenetic tree branch point that represents a common ancestor is called a ____.

Genes that arise via duplication events within the genome of a species and can evolve new functions are named ____, and are distinct from homologous genes in different species.

FinA in Species B and FinA in Species C are considered ____ because they diverged through speciation.

FinA1 and FinA2 in Species A arose from duplication and are ____.

Explain how the orientation of the cleavage of a Holliday junction determines if the DNA products are crossover or not.

Explain how the mutation will affect overall replication fidelity.

Predict the types of mutations that are likely to increase and why.

Describe how mismatch repair would interact with this system to correct errors and why some mutations may still persist.

____ are mRNA segments that can bind ligands to regulate gene expression.

A researcher performs ChIP-seq to identify genes regulated by TFX, a transcription factor. Describe the major steps of ChIP-seq.

Describe how sequencing data is used to identify binding sites.