BIO 310 TERM TEST 2 UPDATED 2024/2025
QUESTIONS AND ANSWERS 100% CORRECT;
University of Toronto
Gene Linkage - ANSWER-each chromosome has several genes carried
-this means that some genes can independently assort
Who first discovered 2 traits that didn't independetly assort? - ANSWERBateson and
Punnet (flower color and pollen shape)
Linkage - ANSWERwhen 2 genes are located together on a chromosome and tend to
transmit with each other.
Linkage groups - ANSWERchromosomes
T/F genes that are far apart in a chromosome can independently assort - ANSWERTrue
Trihybrid Cross - ANSWERa cross involving three traits
Crossing over (general) - ANSWER-Prophase 1: sister chromatids are replicated
-Non sister chromatids of a homologous chromosome exchange DNA segments
-Without crossing over, results in reassorted linked alleles (nonparental or recombinent)
Evidence in Gene Linkage - ANSWER-investigated traits in Drosophila (x-linked, body
color, eye color and wing length)
-found that those 3 traits are close together on the X chromosome
Janssens - ANSWER-Chiasmata microscopically
-proposed that crossing over involves physical exchange
Who realized that crossing over with X chromosomes was consistent with the fly data? -
ANSWERMorgan
Noncrossing over= ? - ANSWERnonrecombinant offspring
Crossing over= ? - ANSWERrecombinant offspring
What does the likely hood of two genes crossing over depend on? - ANSWERthe
distance between the 2 genes on the chromosome
Chi Square Analysis - ANSWER-often used to calculate linkage
,steps of chi square test - ANSWER1. Propose Hypothesis
2. calculate expected values of each 4 phenotypes
3. apply chi square formula
4. compare chi values to chi square chart
Direct evidence of crossing over= recombinant - ANSWER-Harriet Creighton and
Barbara McClintock worked with corn
-crosses followed 2 linked genes
-Chromosome 9 had abnormalities
-correlated the occurance of recombinant offspring with the exchange of segments of
Homologous chromosomes
-with the experiment, you could follow the genes
Genetic mapping - ANSWER-gene mapping/ chromosome mapping
-determine linear order of linked genes along the same chromosome
T/F Each gene has the same locus on the chromosome? - ANSWERFalse. Each gene
has a specific locus at a particular site in a chromosome
What is genetic mapping useful for? - ANSWER-diagnosing diseases
-cloning disease genes
-predict likelihood of gene in child
How do you make a gene map? - ANSWERby doing recombinant analyses
How are genetic mapping experiments carried out? - ANSWERby a test cross
(heterozygote x homozygote recessive)
Map distance formula - ANSWER(# of recombinant offspring)/(total # of offspring) x
100= mu
1 mu= ? - ANSWER1% of recombination
who created the first genetic map - ANSWERAlfred Sturtevante in 1911
2 gene and 3 alleles= how many combinations - ANSWER8
What does a double crossover do? - ANSWERit separates genes, requiring 2
crossovers
Coefficient of coincidence - ANSWERC= (observed # of double crossover)/(expected #
of double crossover)
Mitotic recombination occurs when? - ANSWERduring an early embryonic stage
, Twinspots - ANSWERa pair of mutant sectors within wild type tissue, produce by mitotic
crossover in an individual of an appropriate heterozygous genotype
Genetic variation - ANSWERdifference in alleles and chromosomes
what is allele variation due to? - ANSWERallele variation is due to mutations at the
nucleotide level
Light microscopy - ANSWERstructure and number of chromosomes studied
What is the most popular stain for karyotypes - ANSWERGeimsa stain (G-bands)
Karyotype - ANSWERA picture of all the chromosomes in a cell arranged in pairs
Mutations (general) - ANSWER- change in total chromosome # (duplication or deletion)
-rearranged (translocation and inversion)
How many ways in simple translocation - ANSWER1 way
How many ways in reciprocal translocation - ANSWER2 ways
Consequences of deficiencies depends on - ANSWER-size of deletion
-what chromosomal material was deleted
Terminal deletion - ANSWERdeletion at end of chromosome
Interstitial deletion - ANSWERwhen an internal segment is lost from a linear
chromosome
Example of deletion in humans - ANSWERcri du chat syndrome
Duplication consequences - ANSWER-phenotypic effect
-large piece of chromosome
-correlated with size of duplication
How are duplications caused normally? - ANSWERcause by abnormal events in
recombination (ex misaligned crossover)
Which is more harmful? Duplication or deletion? - ANSWERDeletion
What can duplications provide - ANSWERadditional genes/ gene families (2 or more
genes similar to each other)
Paralogs - ANSWERhomologous genes within a single species
Globin genes - ANSWERancestral globin gene (14 paralogs)
QUESTIONS AND ANSWERS 100% CORRECT;
University of Toronto
Gene Linkage - ANSWER-each chromosome has several genes carried
-this means that some genes can independently assort
Who first discovered 2 traits that didn't independetly assort? - ANSWERBateson and
Punnet (flower color and pollen shape)
Linkage - ANSWERwhen 2 genes are located together on a chromosome and tend to
transmit with each other.
Linkage groups - ANSWERchromosomes
T/F genes that are far apart in a chromosome can independently assort - ANSWERTrue
Trihybrid Cross - ANSWERa cross involving three traits
Crossing over (general) - ANSWER-Prophase 1: sister chromatids are replicated
-Non sister chromatids of a homologous chromosome exchange DNA segments
-Without crossing over, results in reassorted linked alleles (nonparental or recombinent)
Evidence in Gene Linkage - ANSWER-investigated traits in Drosophila (x-linked, body
color, eye color and wing length)
-found that those 3 traits are close together on the X chromosome
Janssens - ANSWER-Chiasmata microscopically
-proposed that crossing over involves physical exchange
Who realized that crossing over with X chromosomes was consistent with the fly data? -
ANSWERMorgan
Noncrossing over= ? - ANSWERnonrecombinant offspring
Crossing over= ? - ANSWERrecombinant offspring
What does the likely hood of two genes crossing over depend on? - ANSWERthe
distance between the 2 genes on the chromosome
Chi Square Analysis - ANSWER-often used to calculate linkage
,steps of chi square test - ANSWER1. Propose Hypothesis
2. calculate expected values of each 4 phenotypes
3. apply chi square formula
4. compare chi values to chi square chart
Direct evidence of crossing over= recombinant - ANSWER-Harriet Creighton and
Barbara McClintock worked with corn
-crosses followed 2 linked genes
-Chromosome 9 had abnormalities
-correlated the occurance of recombinant offspring with the exchange of segments of
Homologous chromosomes
-with the experiment, you could follow the genes
Genetic mapping - ANSWER-gene mapping/ chromosome mapping
-determine linear order of linked genes along the same chromosome
T/F Each gene has the same locus on the chromosome? - ANSWERFalse. Each gene
has a specific locus at a particular site in a chromosome
What is genetic mapping useful for? - ANSWER-diagnosing diseases
-cloning disease genes
-predict likelihood of gene in child
How do you make a gene map? - ANSWERby doing recombinant analyses
How are genetic mapping experiments carried out? - ANSWERby a test cross
(heterozygote x homozygote recessive)
Map distance formula - ANSWER(# of recombinant offspring)/(total # of offspring) x
100= mu
1 mu= ? - ANSWER1% of recombination
who created the first genetic map - ANSWERAlfred Sturtevante in 1911
2 gene and 3 alleles= how many combinations - ANSWER8
What does a double crossover do? - ANSWERit separates genes, requiring 2
crossovers
Coefficient of coincidence - ANSWERC= (observed # of double crossover)/(expected #
of double crossover)
Mitotic recombination occurs when? - ANSWERduring an early embryonic stage
, Twinspots - ANSWERa pair of mutant sectors within wild type tissue, produce by mitotic
crossover in an individual of an appropriate heterozygous genotype
Genetic variation - ANSWERdifference in alleles and chromosomes
what is allele variation due to? - ANSWERallele variation is due to mutations at the
nucleotide level
Light microscopy - ANSWERstructure and number of chromosomes studied
What is the most popular stain for karyotypes - ANSWERGeimsa stain (G-bands)
Karyotype - ANSWERA picture of all the chromosomes in a cell arranged in pairs
Mutations (general) - ANSWER- change in total chromosome # (duplication or deletion)
-rearranged (translocation and inversion)
How many ways in simple translocation - ANSWER1 way
How many ways in reciprocal translocation - ANSWER2 ways
Consequences of deficiencies depends on - ANSWER-size of deletion
-what chromosomal material was deleted
Terminal deletion - ANSWERdeletion at end of chromosome
Interstitial deletion - ANSWERwhen an internal segment is lost from a linear
chromosome
Example of deletion in humans - ANSWERcri du chat syndrome
Duplication consequences - ANSWER-phenotypic effect
-large piece of chromosome
-correlated with size of duplication
How are duplications caused normally? - ANSWERcause by abnormal events in
recombination (ex misaligned crossover)
Which is more harmful? Duplication or deletion? - ANSWERDeletion
What can duplications provide - ANSWERadditional genes/ gene families (2 or more
genes similar to each other)
Paralogs - ANSWERhomologous genes within a single species
Globin genes - ANSWERancestral globin gene (14 paralogs)
