BIOLOGY 1M03 Lecture Notes - Lecture 2: Genotype Frequency, Allele Frequency, Fair Coin
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These all relate to exceptions to the inheritance patterns encountered by Mendel.â
Why do multiple and lethal alleles often result in modifications of the classic Mendelian monohybrid and dihybrid ratios?
Select the four correct statements.
| -When an essential gene is mutated, it can result in a lethal phenotype. There are no classic Mendelian monohybrid and dihybrid ratios. |
| -In the case of codominance, heterozygotes produce gene products from both alleles of a gene. Classic Mendelian monohybrid and dihybrid ratios are modified by codominance. |
| -In the case of incomplete dominance, the phenotype of the heterozygote is distinct from and often intermediate to the phenotypes of homozygous individuals. Classic Mendelian monohybrid and dihybrid ratios are modified by incomplete dominance. |
| -Genes exist in a large number of allelic versions and a diploid organism has two homologous gene loci that may be occupied by different alleles of the same gene. This can result in many different phenotypes for traits, which may not follow typical Mendelian ratios. |
| -When an essential gene is mutated, it can result in a lethal phenotype. This results in a modification of classic Mendelian ratios. |
| -The phenotype of the heterozygous genotype is distinct from and often intermediate to the phenotypes of the homozygous genotypes. The joint expression of both alleles in a heterozygote is called codominance. There are no classic Mendelian monohybrid and dihybrid ratios. |
| -Genes exist in a large number of allelic versions, but in a diploid organism, only one allele of the gene can occupy one homologous gene loci. Classic Mendelian inheritance cannot explain this phenomenon. |
| -Each gene produces a unique gene product. The effect of one allele in a heterozygote completely masks the effect of the other. Classic Mendelian genetics cannot explain this phenomenon. |
Expression vectors inprokaryotes do not make functional eukaryotic gene products inbacteria very well because
Answer Not sure which one ?!
· the codon sequence for prokaryotes is differentthan the codon sequence in eukaryotes | ||
· there are no disulfide bridges formed in proteinsnormally made in prokaryotes | ||
· prokaryotic expression vectors cannot translateeukarytic sequences | ||
· eukaryotic genes have introns, and prokaryotesdon't | ||
· eukaryotic genes have exons and prokaryotesdon't |
I create a knockout mouseusing the agouti/black fur system \. When I cross the agoutioffspring of the originally engineered mouse, I find a ratio of 2agouti mice to 1 black furred mouse. What is the bestexplanation?
Answer not sure which one?!
· The gene knocked out was recessive. | ||
· The gene knocked out was dominant. | ||
· The gene knocked out was a lethalgene. | ||
· The knockput was integrated into a random spot,and did not knockput the original gene. |
A restriction enzyme cuts DNAand leaves the following end
xxCTGCA
xxG
Which of the following could be the sequence of the correspondingend of the other end of the cut DNA?
Answer
· xxG | |||||||||||||||||
· xxC | |||||||||||||||||
· xxCCGAT | |||||||||||||||||
| · xxGGCTA An SNP always occurs dueto Answer
|
I PCR out a mutated gene in apatient with Lisenbee chorea (the inability to dance in acoordinated fashion) and I compare it to another patient with thatsame disease phenotype. One subject had a mutation on chromosome 4,and the other subject couldn't rock it because of a mutation onchromosome 5. This is an exampe of
Answer
· pleitropy | |||||||||||||||||||||||||||||||||||||||||||||||
· locus heterogeneity | |||||||||||||||||||||||||||||||||||||||||||||||
· allelic heterogeneity | |||||||||||||||||||||||||||||||||||||||||||||||
· dominant negative mutation | |||||||||||||||||||||||||||||||||||||||||||||||
| · penetrance In his experiments, Mendelnoted that when two traits are involved in a genetic cross, theyare inherited independently of each other. Though Mendel didn'tknow about chromosomes, this still holds true (mostly)because Answer
Anticipation is caused by amutation that increases in expressivity over subsequentgenerations. Answer · True · False Question 44 I have a genotype that shouldproduce a specific phenotype, but some of the individuals with thegenotype do not demonstrate any evidence of the phenotype. I wouldconsider this an example of Answer
Question Which of the following doesnot occur during the PCR reactions? Answer
Question DNA markers, or variantnon-coding regions of DNA, are DNA polymorphisms that are usefulfor genetic mapping. Answer · True · False |
A mosaic is an organismwith
Answer
· multiple genotypes within one organism | ||
· multiple alleles within one genotype | ||
· more than one color of fur | ||
· transgenes added to the zygote beforedevelopement | ||
· a wt phenotype but a mutated genotype |
Question
Genotype causesphenotype.
Answer
· No, gentoype just influences phenotype. | ||
· Yes, genotype is the DNA sequence that createsphenotype. |
Question
A true genetic chimera can becreated by
Answer
· mutating a gene early on in the development of anorganism resulting in different alleles being present in theadult | ||
· multiple fertilized eggs or zygotes fusing to formone embryo | ||
· adding a transgene to the genome of an organismduring fetal development only | ||
· adding cells of a different species to an adultorganism | ||
· adding a transgene to the genome of an animal atany stage in development |
Question
The ABO blood group can bestbe explained by the concept of _______.
Answer
· dominant traits | ||
· recessive traits | ||
· allelic heterogeneity | ||
· locus heterogeneity | ||
· vampirism |
If a loss of functionmutation creates a dominant phenotype, it may be becauseof
Answer
· haploinsufficiency | ||
· penetrance | ||
· expressivity | ||
· allelic heterogeneity | ||
· locus heterogeneity |
Please select the best matchfor each.
Answer
| Answer
|
A gene mutates, and theprotein produced has a novel way of interacting with the cell, andcreates a new phenotype because of this new functionality. This iscalled
Answer
· pleitropy | ||
· locus heterogeneity | ||
· allelic heterogeneity | ||
· dominant negative mutation | ||
· gain of function dominant mutation |
Question 62
Mutations in the somaticchromosomes may be inherited by the next generation.
Answer
· True
· False
A degenerate PCR primer withmany variant sequences must be used to make multiple copies of agene
Answer
· if only the protein sequence of the gene productis known to construct the primers | ||
· if the DNA you are using is cDNA to constructthe primers | ||
· if the DNA you are using is genomic DNA to becopied | ||
· if the DNA you are trying to copy iscDNA | ||
· if the vector is prokaryotic and the transformedcell is eukarytotic |
Question
Please select the best matchfor each term.
Answer
| Answer
|
Question
A couple goes on MauryPovitch, and the results are in: you are not the father. But noother man impregnated the female (granted, unlikely for a MauryPovitch guest, but work with me here) and he must be the father.DNA analysis claims otherwise, though the child definitely wasmom's (poor thing). What may be going on here?
Answer
· the child is parthenogenic because the motheractually impregnated herself like a shark, and the child's DNA isall mom's | ||
· the child had a mutation that changed the genethat is used to trace paternity | ||
· the child is a mosaic because he is actually a setof twins fused early during fetal development, and therefore camefrom 2 eggs and 2 sperm | ||
· the dad may have germ-line mosaicism, meaning thatthe genotype of his sperm is different from his somaticgenotype | ||
· mitochondrial DNA only comes from mom, so there isno way to tell whobthe baby's father is |
