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3252 Exam 2

Terms in this set (57)

Advantages
-Shorter evolutionary distance from humans
-Stronger conservation of genes, pathways and development
-Similar cell types, organs, systems
-Testing toxicity of substances
WGD
Whole genome duplication
WGD
Doubles all of the genes in the nucleus, producing paralogs
Paralog
Copies of a gene that share same ancestry in its evolutionary history
Homologs
Orthologs and paralogs, both relate to divergence of a common ancestral gene
Repeated WGD
Increase gene copies exponentially, from 1 to 2 to 4 to 8
600
Million years ago that the common ancestor of all invertebrates and vertebrates existed
Paralogs decay
Timeframe that redundant Hox paralogs were lost to mutational decay, since species didn't need that many copies of the genes
Subfunctionalization
Mutations in one or both paralogs are such that redundancy is lost because each copy specializes on only part of the gene's original function. thus both copies are needed
Tissue specific expression
Different tissues express the products of only one of the paralogs
Co expression
Paralogs each of which now have a complementary function that are needed for a normal phenotype
Neofunctionalization
Beneficial mutation in one of the paralogs gives rise to a better working or new function for the gene. Favored by natural selection going forward in generations
Pseudogenization
Accumulation of deleterious mutations renders the gene untranscribable or unstranslational
Mutations
On the genetic code, classified as insertions, deletions, missense, nonsense
Gene dosage selection
Selection constraint maintaining the duplicate genes pretty much unchanged for balance
Bony fishes
8 sets of hox genes
Invertebrates
1 set of hox genes
Tetrapods
4 sets of hox genes
Hox genes
Subset of homeotic genes that determine segment fate along AP body axis
Speciation
New body that results from subfunctionalize or neofunctionalize
Vertebrates
Undergone two whole genome duplications about 500 million years ago
Teleosts
Highest evolvability because they have 2x the genetic dose from an additional WGD
MARRVEL
Model organism aggregated resources for rare variant exploration
7
-Fission yeast
-Brewer's yeast
-Nematode
-Fruit fly
-Zebrafish
-Rat
-Mouse
Zebrafish
Freshwater minnow, females are larger than males in order to carry large clutch of eggs
Nonfunctionalization
Pseudogenization
Subfunctionalization
Gene function subdivides and specializes
Neofunctionalization
Novel gene function arises
Cypriniformes
Huge teleost order, over 3300 species
- Now 8 paralogs, twice our amount
2 orthologs
Teleosts orthologs
4 orthologs
salmonids and carp orthologs
Tetraploidy
Results when two diploid gametes fuse
melanosomes
Melanin-storing vesicles inside of melanocytes
Xanthophores
Release yellowish pigment
Iridophores
Release molecule that flashes a blue reflection at certain angles, a structural color
Adult pigment
Arise from several cell lineages and require thyroid hormone for pattern development
Horizontal banding coloration
...
A single-base mutation in which of the following transporters is responsible for the impairment of melanin storage in the melanosomes in vertebrate melanocytes?
sodium calcium potassium exchanger (NCKX)
The African Clawed Frog, Xenopus laevis, is a _________________ species that arose approximately 17 mya.
allotetraploid
The injection of human tumor cells from a biopsied cancer into an animal model, such as zebrafish, chicken embryos or mice, is typically referred to as a
patient-derived xenograph
Conducting a phenotypic screen of 1,000 zebrafish embryos that have been incubated in a chemical mutagen, followed by genotypic analysis of specific mutant larvae, examined for differences against the genotype of a wildtype control, is an example of forward genetics.
T or F
true
Chronologically order the steps required for a male zebra finch to properly learn its courtship song.
1. hear the song performed by an adult male conspecific (tutor)
2. memorize he song's "spectral properties" (syllables and motifs)
3. repeatedly practice vocalizing to imitate the tutor
4. perform in presence of adult female
Which of the following zebrafish behaviors would be consistent with a symptom of autism spectrum disorder (ASD)? Select all that apply; partial points deduction for incorrect choices.
4 choices
1. swimming repetitively in circles
2. avoidance of conspecifics placed behind a transparent partition in the tank
3. avoidance of robotic zebrafish
4. startles (initiating escape maneuvers) by low amplitude noises
The fish's blood pressure is highest in which of the following vessels?
ventral aorta
Activated Müller glia (MG) are capable of producing which of the following cell types in the zebrafish's retina? Select all that apply; partial points deduction for incorrect choices.
4 choices
1. rods
2. ganglion cells
3. horizontal cells
4. bipolar cells
When zebrafish larvae are exposed to sublethal concentrations of dioxin, this endocrine disrupting chemical skews their sex ratio towards more males. T or F
False
How can the zebrafish become addicted to the same substances that humans often abuse, such as narcotics?
The central nervous system of humans and zebrafish have homologous neural receptors, neurotransmitters, and signaling pathways.
If a single gene of interest is found in Drosophila melanogaster, based on whole genome duplication events, what is the theoretical maximum number of copies of this gene that may be present in Danio rerio?
8
Which amphibian cell type retains positional information, or 'memory', of its orientation within the limb, and proliferate during regeneration to enable correct orientation of their own daughter cells, as well as to other cell types?
grid cells
Which transcription factor expressed in the limb bud of an embryonic tetrapod specifically signals forelimb identity?
Tbx5
Researchers are investigating the potential uses of animal venoms for
all of the above
1. analgesia
2. cardiovascular therapy
3. pesticides
4. anti cancer drugs
Which anatomical and physiological characteristics are commonly found in terrestrial, but not aquatic life stages of anuran amphibians? Select all that apply; partial points deduction for incorrect choices.
4
1. aquaporin 2 in the nephron
2. skeletal appendages that can support body weight
3. urea excretion
4. lungs
In comparison to experimental results from the genetic manipulation of an invertebrate model, what pathologic outcome(s) would suggest that multiple homologs of a disease gene are present in humans? Select all that apply; partial points deduction for incorrect choices. 4
1. In humans, defects in different homologs of the essential gene cause different loss of function diseases due to subfunctionalization
2. different homologs of the essential gene are each expressed in different human organs, and mutations in these duplicated genes cause organ-specific diseases
3. different homologs of the essential gene are each expressed in different stages of early child development, and mutations in each of these duplicated genes cause different diseases
Pathogenic mutations in which of the following human genes, often studied in animal models, is responsible for Li-Fraumeni Syndrome (LFS), a hereditary condition that has been linked to more than eight types of cancers?
tp53
Chronologically order the workflow steps that the Undiagnosed Diseases Network (UDN) initiates upon handling a new patient.
1. Genotype the patient and/or patient's tumor.
2. Search the UDN database for possible matches between the patient's genetic mutation and any previous patients, as well as screen for the existence of homologous mutations in model organisms by searching MARRVEL.
3. Compile the existing bioinformatics on the gene variant based on previous research in animal models.
4. Prioritize and assign biomedical researchers, who will proceed to work on discovering the functional genetics of the novel variant at one or more of the animal model core facilities.
5. Diagnose the patient based on the bioinformatic and model organism research and suggest a therapeutic plan.
A strain of zebrafish has an otherwise healthy nervous system but is unable to regenerate its spinal cord after it has been cut, unlike the other colonies kept in the lab. What is the most likely explanation for this loss-of-function phenotype?
the strain lacks ctgfa
Match the following transcription factors whose expression during embryonic development leads to the key segments or axes of the vertebrate limb.
1. Heart and neural crest derivatives expressed 2 (Hand2)
2. Meis
3. Hoxa11
4. Hoxa13
1. Expressed as a morphogenetic gradient to establish the anteroposterior axis of the developing limb bud
2.early expression in the limb bud gives rise to the stylopod
3. temporally intermediate expression in the limb bud gives rise to the zeugopod
4. late expression in the limb bud gives rise to the autopod
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