Genetics 3 – Flashcards
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A unique trait of embryonic stem cells that make them useful for generating knockout animals is that they:
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are totipotent
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What is true of DNA arrays:
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They can be used to compare the expression of mRNA from all the genes in cells under two different environmental conditions
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Most polymorphisms do not result in phenotypic difference since they are typically:
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Either silent mutations or are in non-coding regions
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The proportion of individuals in a population that are of a particular genotype is the:
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genotype frequency
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The term for the type of mutation that results in a loss of material from the genome is:
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deletion
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The total genetic relatedness of two siblings is:
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0.5
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They Hardy-Weinberg equation is best at predicting short term genotypic frequencies since:
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Over the long term some of the assumptions of the equation will not be true
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Currently the two main vectors for delivery of therapeutic genes for human gene therapy are:
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AAV and retroviruses
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Biological ancestry describes the:
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Parentage and not shared genes
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Which of the following sex chromosome aneuploidies is not usually seen in live births:
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YO
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What is one problem associated with using retroviruses as human gene therapy vectors:
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Their random integration into the host chromosome may result in detrimental mutations
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Robertsonian translocations result from which of the following:
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Breaks occur at or near the centromeres of two acrocentric chromosomes followed by the reciprocal exchange of broken parts
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The type of chromosomal rearrangement that recognizes the DNA sequence within one chromosome is known as a(n):
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inversion
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The proportion of individuals in a population that are of a particular phenotype is the:
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phenotype frequency
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Multifactorial inheritance is observed in phenotypes that show typically
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A bell-shaped distribution
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A number if interacting genes produce quantitative inheritance. The transmission of these genes can be seen in the phenotypical pattern of:
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Continuous variation in phenotypic expression
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The sum total of all alleles carried in all members of a population is called its:
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gene pool
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In an experiment to distinguish genetic versus environmental effects on a phenotype it is important to make sure that the test individuals:
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Are as genetically identical as possible
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How could PCR be used for the detection of a SNP:
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The PCR reaction products would need to be sequenced
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Deletions and duplications are most often caused by:
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Unequal crossing over
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Many human recessive genetic diseases are maintained despite continuing selection against them because:
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Heterozygotes have a higher fitness than either homozygote
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What are the four major classes of chromosomal rearrangements:
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Inversions, duplications, translocations, deletions
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Which of the following is NOT one of the assumptions of the Hardy-Weinberg law
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Non-random mating occurs within the population
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Multifactorial traits:
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Are affected by both genetic and environmental factors
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Why are conditional knockout animals desirable
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Genes that are essential for development can be deleted in the adult
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Transgenic organisms can help clarify which gene may be responsible for a particular phenotype since:
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Individuals with the phenotype frequently carry other mutations as well
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Which of the following polymorphism would you predict to most likely affect an individual's phenotype
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An SNP in the start codon of a protein-coding gene
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By definition linkage disequilibrium means that
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Two allelic variants can correlate with the presence of a particular phenotype
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What evidence supports the hypothesis that humans originated in Africa:
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Mt sequence variation is the highest in African populations
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How has DNA sequencing clarified the relationship between modern humans and other lineages
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It has demonstrated that modern humans interbred extensively with other lineages
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The term for when a piece of one chromosome attaches to another chromosome is
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Translocation
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Mapping a disease gene in humans requires
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Large numbers of mapped physical markers with complete genomic coverage and small families with pedigrees and DNA sequences
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Which of the following is NOT true about monozygotic twins:
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They have a genetic relatedness of 0.5
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SNP is the acronym for
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Single nucleotide polymorphism
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The loss of allelic variation due to an event that decreases the size of the entire population is called
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population bottleneck
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Down syndrome can result from
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Three copies of chromosome 21
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In forensics analysis 13 loci are typed and the probability of finding an individual in a population with that specific combinations of SSRs is calculated based on
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The Hardy-Weinberg Law
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Knockin mice can be created using the Cre-lox system. In this procedure the mutation to be knocked in is
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Cloned outside of the two lox sites
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Twins from two individuals zygotes (dizygotic twins)
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Are related genetically the same as non-twin siblings
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The total phenotype variance (Vp) is
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The sum of genetic variance (Vg) and environmental variance (Ve)
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What techniques can be used to focus on a limited number of genes as being involved in a disease
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Comparison of genome sequence between variant databases
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To create transgenic mice DNA is injected into
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A pronucleus of a zygote
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Karyotypes generally remain constant within a species because:
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Genetic instabilities produced by genomic changes usually are at a selective disadvantage
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What is a limitation of using pedigrees for positional cloning:
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Some matings may not be informative
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Why do the alleles that confer insecticide resistance in mosquitoes become less frequent in the population when insecticide application is discontinued
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The alleles for resistance had a negative fitness cost
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Positional cloning requires knowledge about the
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Map location of a gene or other marker
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New mutations that arise within a population are typically lost primarily due to
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Populations are of a finite size and new mutations are frequently lost by genetic drift
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Why is it possible to find a unique genetic profile for an individual using the information about a relatively few SSRs
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There is a high variability of SSRs in the population
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IN general, which type of mutation usually has the greatest probability of a lethality:
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deletion
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Why are organisms with an odd number of chromosome sets usually sterile
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Almost all gametes will have an unbalanced set of chromosomes
