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Eukaryotic gene expression
Prokaryotic gene expression
Population genetics
Quantitative genetics
Evolution
100
All of the cells in a eukaryotic organism (with the exception of reproductivecells) a. Contain the same genome b. Express the same genes c. Produce the same transcription factors d. Both B and C
What is: A. B and C are both FALSE
100
Which of the following is true of the lac operon in E. coli? a) The operon is only switched on in the absence of lactose in the growth medium. b) The lac operon messenger RNA is a polycistronic mRNA (it carries information for synthesis of several proteins) c) The enzyme β-galactosidase is only produced in large quantities when the lac repressor is bound to the operator. d) The promoter is the binding site for the lac repressor.
What is: B
100
The dominant allele is the most common allele in the gene pool, true or false
FALSE: example, blood type in humans. O is recessive, and also most common.
100
What does this equation give you h^2 = VA/VP
What is narrow sense heritability
100
Both whales and bats use echolocation. What is this likely an example of?
What is: convergent evolution
200
Changes in DNA that can be inherited from cell to cell (like DNA methylation or chromatin conformation) that do NOT involve changes to the sequence itself are:
What is: epigenetic inheritance
200
This type(s) of bacteria may function as a partial diploid: F+, F-, F', and/or Hfr?
What is: Just F'
200
In the Hardy-Weinberg equation, 2pq equals the percentage of _____.
What is: heterozygotes
200
Apart from additive genetic variation, what OTHER kinds of variation contribute to VG?
What is dominance and epistasis
200
Neighboring populations A and B can interbreed, and B can breed with both A and B. However, A and C are not geographically next to each other, and if they are brought to the same environment, they *can't* interbreed. What is this?
What is: Ring Species
300
Genes that are constitutively active in all cells (like the genes for producing ribosomes, or membranes) are sometimes referred to as:
What is "housekeeping genes"
300
Why are lacI- or lacI-s 'trans' mutations?
What is: they are mutations in DNA that codes for proteins, vs. mutations in regulatory DNA. They can influence the expression of genes on a plasmid
300
If four percent of a population shows a recessive trait, what will be the frequency of carriers in the following generation?
q^2 = 0.04 q = 0.2 p =1-q or 0.8 What is: 2pq -> 2 * 0.2 * 0.8
300
What is the difference between broad sense and narrow sense heritability?
What is: broad sense heritability is the percentage of phenotypic variance in a population due to genetic factors. narrow sense heritability is the percentage that can specifically be passed from parent to offspring (additive genetic variance)
300
What are some advantages to evolutionary changes happening in regulatory DNA (cis mutations) vs. in protein coding sequence (trans mutations)
What is: proteins are more likely to be pleoitropic! Cis mutations only affect the genes that they directly regulate. Also easier to tinker, more likely to have more of a protein, or less of a protein being an advantage, than to develop a totally new protein.
400
What are three differences between prokaryotes and eukaryotes that influence gene expression?
What is : ESCORT acronym E = enhancers (common in eukaryotes) S = splicing (common in eukaryotes, proks don't have introns) C = chromatin (prokaryotes don't have histones, euks do) O = operons (prokaryotes only) T = transcription and translation (prokaryotes have this simultaneous, eukaryotes have this separated between nucleus and cytoplasm) prokaryotes are single celled, eukaryotes can be multi-cellular. prokaryotes are haploid, eukaryotes are diploid. prokaryotes have one circular chromosome, eukaryotes have multiple linear chromosomes that are generally compacted around histone proteins in 'chromatin'. prokaryotes have no nucleus, eukaryotes have a nucleus which leads to separation of transcription and translation.
400
What is a reason bacteria might use operons for gene regulation?
What is: when a number of genes need to be turned on or off under the same condition (proteins needed to synthesize tryptophan, or digest lactose), it's efficient to transcribe them all together.
400
For a particular human population, if the allelic frequency of the O allele for blood type was .1, and the frequency for the B allele was .5, what would be the allelic frequency for the A genotype?
O is 0.1, B is 0.5, A must be 0.4 AO frequency will be 2 * 0.4 * 0.1 0.24 total
400
Many life history traits (fecundity, lifespan, etc.) have a heritability close to 0. Why do you think this is the case?
What is traits that are very important tend to be fixed at the highest fitness combination of alleles, and not variable due to heritable genetics--> no genetic variation for the trait in the population
400
What are some reasons that DNA sequences might change at different rates over evolutionary time? E.g. why don't molecular clocks always work?
What is: Species with faster generation time will have faster rates of evolution (evolution happens much faster in E.coli than in humans, and faster in humans than in elephants). Also, selection can lead to sequences changing more slowly or more quickly. Also, mutation rates can vary over time.
500
A classic example of phenotypic plasticity is caste determination in social insects. Whether a female ant becomes a worker, soldier, or queen is determined by the food she is fed. Would you say this this an example of VG, VE, or VG:VE?
What is: VE-- this is entirely environmental. Ants becoming queens has nothing to do with their genotype.
500
Under what conditions will the trp operon attenuate?
What is: Translation is proceeding rapidly, ribosome does NOT stall at the Trp leader sequence. The 1+2 and 3+4 hairpins form. 3+4 is a transcription termination sequence.
500
In a study of the Hopi, a Native American tribe of central Arizona, Woolf and Dukepoo (1959) found 26 albino individuals in a total population of 6000. This form of albinism is controlled by a single gene with t wo alleles: albinism is recessive to normal skin coloration. Can we calculate allele frequencies from this information? why or why not?
If the population was in Hardy Weinberg Equilibrium, maybe-- we could estimate the frequency of the albinism allele from the q^2 value. However, real populations are almost never in HWE, so we have no idea how many people are heterozygous.
500
Natural selection can only act on traits that have a narrow sense heritability higher than 0. Why might this be the case, in the context of the breeders equation?
What is: Natural selection can only occur when a trait has a fitness advantage (which means the breeders will have a mean value different than the population average), and it only matters if it can be passed to the next generation. Dominance interactions cannot be transmitted, and neither can environmental effects.
500
How can Hox genes be considered both orthologs and paralogs?
What is: The same gene family of transcription factors responsible for body patterning is present in very diverse species (all muticellular animals). Equivalent genes between species is orthologs. In many more complex animals, whole genome duplications or duplications of single genes have led to expansion of this gene family, copies of the same gene within species (paralogs)