Genetic Mapping In Eukaryotes
This question bank verified by Studydeets
Questions Bank
- Genetics: An IntroductionDNA: The Genetic MaterialDNA ReplicationGene FunctionGene Expression: TranscriptionGene Expression: TranslationDna Mutation,DNA Repair,and Transposable ElementsGenomics: The Mapping and Sequencing of GenomesFunctional and Comparative GenomicsRecombinant DNA TechnologyMendelian GeneticsChromosomal Basis of InheritanceExtensions of and Deviations From Mendelian Genetic PrinciplesGenetic Mapping in EukaryotesGenetics of Bacteria and BacteriophagesVariations in Chromosome Structure and NumberRegulation of Gene Expression in Bacteria and BacteriophagesRegulation of Gene Expression in EukaryotesGenetic Analysis of DevelopmentGenetics of CancerPopulation GeneticsQuantitative GeneticsMolecular Evolution
Question 1
Free
Short Answer
Please select the best match for each term.
A)F1 to mahogany eyes and stubble bristles
B)Recombinants divided by the total × 100
C)Mahogany eyes and normal bristles
D)Wild-type red eyes and normal bristles.
E)Genes that do not segregate independently
-1)Parental type
2)Recombinant type
3)Testcross
4)Gene linkage
5)Map unit
Check answer
Question 2
Free
Multiple Choice
If genes are linked and an F1 is testcrossed,
Choose correct answer/s
the genes cannot separate.
they can produce only one phenotype.
they only produce homozygotes.
they produce more recombinant phenotypes than parental phenotypes.
they produce more parental phenotypes than recombinant phenotypes.
Check answer
Question 3
Free
Multiple Choice
Crossing-over is
Choose correct answer/s
the place on a homologous pair of chromosomes at which a physical exchange occurs.
an extremely rare event.
an event that only takes place during meiosis.
the reciprocal exchange of homologous regions of chromatids.
not useful in mapping genes.
Check answer
Question 4
Free
Multiple Choice
Genes that are linked
Choose correct answer/s
segregate to opposite poles during meiosis.
do not assort independently during meiosis.
segregate independently during meiosis.
are on nonhomologous chromosomes.
are always on the X chromosome.
Check answer
Question 5
Free
Multiple Choice
A chi-square analysis of linkage between genes k and f produces a P value of 0.99.What is the likelihood that these two genes are linked?
Choose correct answer/s
99%
10%
9.9%
1%
None of these
Check answer
Question 6
Multiple Choice
If an AABB strain is mated with an aabb strain,an AB gamete produced by the resulting F1 is
Choose correct answer/s
impossible.
parental.
recombinant.
the most common.
None of these
To unlock the question
Question 7
Multiple Choice
During a dihybrid cross involving two linked genes,18% of the resulting gametes showed a recombinant genotype.These two linked genes are ________ map units apart.
Choose correct answer/s
0.18
18
32
180
1.8
To unlock the question
Question 8
Multiple Choice
If two genes are not linked,then the expected phenotypic ratio resulting from a testcross is
Choose correct answer/s
9:3:3:1.
1:2:1.
3:1.
1:1:1:1.
1:1.
To unlock the question
Question 9
Multiple Choice
In a species of Drosophila,genes q and r are found on the same chromosome 20 centimorgans apart.A cross was made between the following individuals: 
What proportion of the offspring would you expect to have the wild-type phenotype?
Choose correct answer/s
0.10
0.20
0.40
0.80
None of these
To unlock the question
Question 10
Multiple Choice
One map unit is equal to a recombination frequency of
Choose correct answer/s
1%.
5%.
10%.
50%.
100%.
To unlock the question
Question 11
Multiple Choice
T.H.Morgan and his colleagues found that among the offspring of genetic crosses,parental phenotypic classes were the most frequent,while recombinant classes occurred less frequently.This observation led Morgan to conclude that
Choose correct answer/s
all genes are linked.
alleles of linked genes assort independently.
alleles of some genes assort together.
genes on different chromosomes assort independently.
genes on different chromosomes do not assort independently.
To unlock the question
Question 12
Multiple Choice
When does crossing-over occur?
Choose correct answer/s
Prophase I of meiosis
Prophase II of meiosis
Interphase prior to meiosis
At any time during the second meiotic division
At any time throughout division
To unlock the question
Question 13
Multiple Choice
A DNA mutation that gives a distinguishable phenotype for a chromosome or gene is a
Choose correct answer/s
recessive allele.
lethal mutation.
parental type.
linkage group.
genetic marker.
To unlock the question
Question 14
Multiple Choice
The closer together two genes are on a chromosome,
Choose correct answer/s
the more likely there will be a recombination event between them.
the less likely there will be a recombination event between them.
the greater the chance that a double crossover will occur between them.
the more likely they are to be epistatic.
the less likely they are to be good genetic markers.
To unlock the question
Question 15
Multiple Choice
In the offspring resulting from an F1 testcross,what percentage of recombinant phenotypes is expected if the genes under study are independently assorting?
Choose correct answer/s
5%
33%
50%
90%
The percentage cannot be predicted.
To unlock the question
Question 16
Multiple Choice
A two-point testcross is a cross between
Choose correct answer/s
a double heterozygote for two linked genes and a double recessive genotype.
a heterozygote for one of two linked genes and a double recessive genotype.
a double heterozygote for two linked genes and a homozygous dominant genotype.
a heterozygote for one gene and a homozygote for another.
individuals with two different genetic markers.
To unlock the question
Question 17
Multiple Choice
How many phenotypic classes may be generated from a three-point testcross?
Choose correct answer/s
(3)2 = 9
(2)3 = 8
(3)3 = 27
(2)2 = 4
It cannot be predicted.
To unlock the question
Question 18
Multiple Choice
Interference is a phenomenon in which
Choose correct answer/s
no double crossovers occur among nearby genes.
the number of observed double crossovers is greater than the number of expected double crossovers.
the number of observed double crossovers is less than the number of expected double crossovers.
the occurrence of one crossover interferes with the formation of another crossover nearby.
Both C and D
To unlock the question
Question 19
Multiple Choice
Without performing any calculations,which of the following is the gene order?
Choose correct answer/s
abc
acb
cab
+++
None of these
To unlock the question
Question 20
Multiple Choice
Which gene pair is closer together; i.e.there are fewer map units between them?
Choose correct answer/s
a → b
b → c
a → c
a → b and b → c are the same length
a → c and b → c are the same length
To unlock the question