ANSWERS TO Exam Questions from Exam 3 Eukaryotic Gene Regulation Genome Modifications in Eukaryotes Population Genetics 1 Consider an autosomal recessive trait that occurs at a frequency of 10 6 in a specific human population that is at Hardy Weinberg equilibrium ie random mating is occurring a b 85 c decrease d all three of these choices could act to keep q constant 2 You are studying regulation of the Wrm1 gene a yeast gene that is expressed in response to heat a constitutive b recessive c trans d dominant negative activator e Tetrad Type A Number of these tetrads out of a total of 90 86 Classification of these tetrads PD NPD or TT PD Color in the spores that would be blue in color when growing on the following plates X gal 24 C X gal 36 C NOTE that the two plates are replicas so the top spore on the left plate has the same genotype as the top spore on the right plate Tetrad Type B Number of these tetrads out of a total of 90 4 Classification of these tetrads PD NPD or TT TT Color in the spores that would be blue in color when growing on the following plates X gal 24 C X gal 36 C 3 The scenario in this question asks a biological question that can be addressed by creating genetically engineered mice i pronuclear injection ii the d Nhe gene iii fertilized egg iv NheJ NheJ v randomly vi no vii you would have to cross two of the transgenic mice you made and screen for mice that are NheJ NheJ d NheJ viii if these mice are UV sensitive then the two genes are not interchangeable if these mice are UV sensitive then the two are interchangeable 4 You are studying how yeast cells grow on the sugar maltose as a carbon source a A negative regulator maltose B positive regulator maltose C negative regulator glucose b constitutive c maltose B A glucose C maltase d Region 2 e Deletions 4 and 5 5 You have a mutant mouse that displays the phenotype of white fur instead of the wild type color for this strain which is brown fur 1 gene targeting 2 the allele of whfr that is found in the mutant mouse 3 ES cells 4 wild type 5 The whfr locus 6 Mate the chimeric heterozygote that results to wild type to get a non chimeric heterozygote Then mate two non chimeric heterozygotes together and 1 4 of their progeny will be the mouse you want 7 if the mouse has white fur then the whfr mutation itself is sufficient to cause the white fur phenotype If the mouse is brown then a combination of mutations must have caused the white mutant mouse to be white 6 An allele that causes the recessive phenotype of microcephaly has a frequency q 0 0001 in a randomly mating population in Hardy Weinberg equilibrium 8 a frequency 10 b h 0 00009 c q 0 0000447 7 You are studying a yeast strain that will grow using the sugar raffinose as a carbon source a the mutations both give recessive phenotypes and are in different genes b uninducible c raffinose 2 3 Raf1 d you would get all PDs which would each have two uninducible spores and two constitutive spores 8 Suppose that in an isolated population there exists a very rare inherited anemia which is autosomal recessive a b c d 2 q 2pq which approximately equals 2q 1 16 0 008Fq 0 001q 2 e 0 008 Fq q so q 0 001 9 You are studying the sihZ gene in mice and you isolate a mutation called regX that disrupts proper transcriptional regulation of the sihZ gene a pronuclear injection b insert the regX mutant allele distal from the sihZ gene c use the regX allele from the regX mutant animal Do not put the sihZ open reading frame on this fragment This fragment will integrate randomly d fertilized egg wild type animal e no additional breeding f If the sihZ gene is properly regulated in the transgenic animal then the element works in cis and is a regulatory DNA region upstream of the sihZ gene If the sihZ gene is improperly regulated in the transgenic animal then the element works in trans and encodes a regulatory protein 10 A early nonsense mutation in the yeast URA9 gene gives an intermediate level of growth without the nucleotide uracil being provided in the growth medium Ura a You have isolated a suppressor mutation that is unlinked to the original mutation This suppressor mutation alone gives a Ura phenotype The suppressor may be in a tRNA gene causing a nonsense suppressing allele of this tRNA gene b You have isolated a synthetic mutation that is unlinked to the original mutation This synthetic mutation alone gives a Ura phenotype The synthetic mutation may be in another gene that is partially necessary for synthesis of the nucleotide uracil such that without the function of this gene the cell is Ura but without the function of this gene and without the function of Ura9 the cell is fully Ura c The suppressor mutation and the synthetic mutation are tightly linked d The tRNA suppressor mutation must also suppress the mutation will isolated in part b Thus the synthetic mutation which on it s own gives a Ura phenotype also must be a nonsense mutation of the same category opal ochre amber as your original mutation This allows a triple mutant strain with the original mutation the synthetic mutation and the suppressor mutation to have a Ura phenotype 11 Trekking in the Himalayas you discover a founder generation of 1000 goats barricaded on all sides by high peaks and massive glaciers a f A 0 3 and f a 0 7 b no c f A 0 3 d f AA 0 09 and f Aa 0 42 and f aa 0 49 12 The scenario in this question asks a biological question that can be addressed by creating genetically engineered mice i pronuclear injection ii the PrfM gene from the mouse that can smell perfume iii fertilized egg iv a homozygous knockout of PrfM v randomly vi no vii none viii If you ever generate a mouse that can smell then the mutation was intragenic If you never get a mouse that can smell then the mutation was extragenic 13 You are studying the regulation of Gln1 a yeast gene involved in glutamine synthesis a constitutive b yes at 37cM c ten of those 17 spores d glutamine 8 7 1 14 Albinism is a rare condition that is inherited as an autosomal recessive phenotype in many animals including humans a q 0 0135 b Uncle niece 1 8 Grandparent grandchild 1 4 c Fq 1 16 0 0135 d 0 0058 15 The genetics of the eye disease known as retinitis pigmentosa RP are complex in humans with many dozens of genes implicated a 1 transgene 2 mutant RP5 3 fertilized egg 4 wild type 5 random 6 none b 1 gene targeting 2 the RP11 gene disrupted by …
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