Exam 4 Flashcards
how is relative fitness (W) calculated?
Wx = (# of offspring of x) / (# of offspring of the one with the highest fitness)
gene with the highest reproductive value (most offspring) will always have a fitness of W = 1.0 and other fitness values will be determined relative to that one
what is a population?
the term for a group of organisms of the same species that can interbreed and live in an isolated group
monomorphic vs polymorphic vs monogenic vs polygenic
monomorphic: a gene that has only one allele
polymorphic: a gene with two or more alleles
monogenic: controlled by a single gene
polygenic: controlled by more than one gene
what is directional selection and what is an example?
when the survival of one extreme phenotype or the other is favored, dark winged butterflies are favored in dark environments as opposed to light winged ones
what is balancing selection and what is an example?
when the maintenance of two or more alleles are favored, heterozygotes with sickle cell anemia are more likely to survive when infected with malaria, or pollinators visiting more rare flower colors more which keeps one color from becoming too common or rare
what is disruptive selection and what is an example?
when survival of two different phenotypes is favored, more than one snail shell color is preserved because different environments have different shell colors that are favored
what is stabilizing selection and what is an example?
when survival of individuals with intermediate phenotypes is favored, laying a medium amount of eggs is favored as opposed to laying too many to take care of or too few to survive
in the field of population genetics and evolutionary biology what does the term fitness refer to?
the ability to survive and reproduce
what is the Hardy-Weinburg equation and what does each variable represent?
p^2 + 2pq + q^2 = 1
2pq: frequency of heterozygous individuals (Gg)
p^2: frequency of homozygous dominant individuals (GG)
q^2: frequency of homozygous recessive individuals (gg)
used to determine the expected frequencies of the genotypes in a population if they are not changing
if a population is at Hardy-Weinburg equilibrium for a particular gene what does this mean?
the population is not evolving
what is genetic drift?
random changes in allele frequency as a result of chance events, therefore is a small group of animals establishes a new population away from the original group then the new one is likely to be different from the original one
what is gene flow?
when individuals migrate between populations with different allele frequencies, pollen from one flower being carried to a new population or animals mating with another population
what is nonrandom/assortative mating?
when individuals choose to mate with those of a specific phenotype as opposed to choosing randomly
what is the correlation coefficient and what is the value of its degrees of freedom?
correlation coefficient is the strength of the association between two variables, its degrees of freedom is n-2
what is variance and what is the value of its degrees of freedom?
variance is the statistic to evaluate variation in a population, its degrees of freedom is n-1
what is covariance and what is the value of its degrees of freedom?
covariance is the degree of variation between two variables within a group, its degree of freedom is n-1
what are quantitative traits?
quantitative: study of traits that can be determined numerically and categorized as anatomical, physiological, behavioral, and human diseases
what characteristics do quantitative traits usually have?
environmental influence, polygenic basis, and continuous distribution
what is heritability and how do you interpret its value?
heritability is a measure of whether observed variation is due to genetics or the environment
a heritability value of 1 means all of the variation is due to genetics
a heritability value of 0 means all the variation is due to the environment
how can you determine the total variance of a population for a quantitative trait?
sum the genetic and environmental variances
what does quantitative trait loci mapping determine?
determines relationships between quantitative traits and molecular markers such as RFLPs
what is a critical factor for preparing genomic DNA to make a library for genome sequencing?
partially digesting the DNA with a restriction enzyme
which technique is needed when performing an RFLP analysis to test for a genetic disease?
southern blot
why is Sanger sequencing no longer used for genome sequencing?
the products of a sequencing reaction need to be separated to determine the DNA sequence, it is relatively slow, and it is relatively expensive
what is used as “probes” to study protein expression in a protein microarray?
antibodies
how can you determine if genes are homologs?
if genes are orthologs (genes at the same locus) they will have the same number, if genes are paralogs (related genes within or between species) there will be a corresponding genes in the other species where it is blank for one species, orthologs and paralogs both count as homologous species
what are different types of BLAST searches and what are they used for?
blastn: nucleotide vs nucleotide (used for DNA to DNA research)
blastx: translated nucleotide vs protein database (used for DNA to cDNA research)
blastp: protein vs protein database (used for amino acid to protein research)
what is mapping?
the experimental process of determining the relative location of genes or other segments of DNA along individual chromosomes
what is replacing microarrays as a powerful tool to study gene expression?
transcriptome sequencing
what do chromatin immunoprecipitation (chIP) assays determine?
used to determine if proteins can bind to a particular region of DNA
what does mass spectroscopy determine?
determines the amino acid sequence of a protein from a gel and then the amino acid sequence can be searched against a database to determine gene identity, also used to identify protein covalent modifications
what is proteomics?
the study of the proteome (all of the proteins produced) and how they interact with each other
in proteomics if you identify a protein that is differentially expressed between two samples by 2D electrophoresis, what technique could you use to determine the gene that it came from?
mass spectroscopy
what animals do humans share 30%, 75%, 80%, and 98% of their genome with?
30%: yeast
75%: dogs
80%: mice
98%: chimpanzees
how many genes do most eukaryote genomes usually contain?
~ 25,000
the RNA level _______ the steady-state level of the corresponding protein, and the post-translational modification of the protein ________ from RNA data?
doesn’t necessarily reflect, can’t be determined
what is metagenomics?
the study of the collective microbial genome in an environmental sample
what is comparative genomics?
compares whole genomes of different organisms to answer questions about genetics and other aspects of biology (dogs being used as a model system for studying heritable genetic diseases in humans)
in a disease that is due to a single genes, the concordance among monozygotic twins should be what?
100%
what of the following best describes most cancers?
the statistical likelihood for developing many types of cancer is heritable
what are proto-oncogenes and oncogenes?
proto-oncogenes: normal un-mutated version of oncogenes
oncogenes: mutations in these genes promote cancer by keeping the cell growth signaling pathway permanently on, promoting unregulated cell division
what are tumor suppressor genes?
genes that prevent the proliferation of cancer cells, mutations that inactivate these genes make it more likely than cancer will occur, regulate cell-cycle checkpoints and initiation of apoptosis
what kind of mutation in oncogenes and tumor suppressor genes result in a gain or loss of function?
missense mutations because they can trade GDP for GTP on a protein which causes it to be activated and divide
what do cyclins/cyclin-dependent kinase complexes control in normal cells?
the cell cycle
what are metalloproteinases?
a class of genes that is up-regulated in the process of metastasis, present in high levels in malignant tumors
what is the p53 gene and what class of gene is it?
a gene associated with 50% of all human cancers since its mutated form can no longer bind to DNA properly meaning it cannot activate p21 to act as a stop signal, allowing cells to divide uncontrollably, it is a tumor suppressor gene
what are the steps of cell division that lead to the development of a tumor?
initial tumor cell starts to experience benign growth, then malignant growth starts to spread to the surrounding tissue, cells then become metastatic (moves to different area of the body) and enter the bloodstream, angiogenesis is the recruitment of blood vessels by a tumor
what would a mutation that causes a loss of cell cycle regulation alone lead to?
a benign tumor
under strictly controlled conditions, a short DNA probe will hybridize in vitro only its complementary sequence and not sequences that differ from it by even one nucleotide, this information is used in medicine to design ……
ASOs
the first successful case of gene therapy involved transforming human cells with a “wild-type” (non-mutated) copy of a gene, for what kind of genetic disease can this approach be used?
a disease caused by genetically recessive mutation in an essential gene
what is amniocentesis and chronic villus sampling?
amniocentesis: when fetal cells are obtained from the amniotic fluid and genetically tested
CVS: cells are obtained from the placenta part of the fetus and genetically tested, can be performed earlier in the pregnancy than amniocentesis
what is an advantage of ASO testing for prenatal diagnosis in contract to RFLP analysis?
ASO testing can be used for mutations that do not create or destroy a restriction site
which method of post-transcriptional regulation of mRNA is utilized in some types of gene therapy?
RNA interference
which of the following scenarios could RNAi be used to treat?
a disease caused by over-expression of a particular gene
which component of a CRISPR array are responsible for determining the specific sequence of the DNA target that will be cleaved?
spacer regions
how long have humans been using biotechnology?
> 10,000 years
what are the advantages of using recombinant DNA technology to produce insulin in bacteria rather than the previous methods?
the insulin produced has less side effects because it is “human” insulin, it is cheaper, and it is safer
which organism is used by molecular biologists to introduce genes into plant genomes?
agrobacterium tumefaciens
which gene widely used in genetically modified crops encodes a protein that is also widely used in organic agriculture?
cry from bacillus thuringiensis
how do you determine the sequence of primers that could be used to amplify a DNA sequence by PCR?
(DNA sequence runs 5’ to 3’)
first primer is the same as the first part of the sequence (5’ to 3’)
second primer is the complementary strand running the opposite way as the template strand (primer runs 5’ to 3’ starting at the 3’ end of the template strand)
question 51 on exam 2
if a single DNA segment is transferred from one (non-homologous) chromosome to another by recombination, what has occurred?
a simple translocation
which of the labeled structures are complexes of proteins and nucleotide polymers?
1 and 4
(question 4 on exam 1)
what is the basic repeating structural unit of chromatin?
a nucleosome
which of the following classes of RNA have catalytic activity?
rRNA
in eukaryotic translation, once the stop codon UGA is reached, what triggers the release of the peptide and the disassembly of the ribosome?
binding of eRF1 to the A site of the ribosome
which of the following is encoded by the mRNA COVID vaccines?
spike glycoprotein
what feature engineered into plasmid cloning vectors allows you to visually select bacteria transformed with plasmids that contain DNA inserts from those with plasmids that do not?
lac Z
a small effector molecule that increases the level of transcription is a called a/an?
inducer
what does deamination of 5-methyl cytosine cause?
C to T mutations
when studying a genetic cross, the second generation following the initial cross is identified by which of the following?
F2 generation
the observable characteristics of an organism are called its _________?
phenotype
hypothesis: two particular genes segregate independently. After investigation: experimental data v’s expected data gives a X^2 = 0.5 (1 degree of freedom). What can you conclude?
the genes likely segregate independently
question 39 on exam 3
the production of gene families, such as the globin genes, is the result of _________?
gene duplications
