MBG 2400 Exam Review Questions With Correct Answers
1. Polymorphism
:Ans- the presence of genetic variation within a population, upon which
natural selection can operate
2. What are B and B in an organism's DNA?
:Ans- Represent a difference (allele or polymorphism) in the DNA sequence at a
location (locus) in the organisms genome. The dual strand composition makes it
convenient to use letters of the alphabet and capitalize one.
3. 3 factors affecting independence and F2 ratios
:Ans- Pleiotropy, epistasis, linkage
4. Pleiotropy
:Ans- one locus affects two or more traits
5. Epistasis
:Ans- alleles at one locus affect the expression of alleles at a different locus
6. Linkage
:Ans- two or more loci are on the same chromosome
7. How does W dominant allele for white cat also cause deafness?
:Ans- -
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,Melanocytes
- produce fur pigmentation but are also present for electrical transmission to the
brain
- defective melanocyte development means no pigment or electrical signals = white
and deaf
8. How does W allele for white cat display epistasis?
:Ans- W masks all other colour and pattern genes and therefore shows dominant
epistasis, ww allows expression of colours and patterns
9. Calculating allele frequencies by counting
:Ans- separate genotypes into how many A and a alleles for each, add up for each
and divide by total # alleles
OR
p = P + 0.5H
q = Q + 0.5H
and P + H + Q = 1
where P is freq of homo dominant, H is freq of hetero and Q is freq of homo recessive
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, 10. Hardy-Weinberg Equilibrium
:Ans- Present in a large, random mating population in the absence of migration,
mutation and selection
"Allele frequencies and genotypic frequencies remain constant and genotypic fre-
quencies are determined by allele frequencies"
11. What does it mean to say that Hardy Weinberg Equilibrium is a utopian
state?
:Ans- Most populations break some or all of the rules
12. Do p and q change with random mating?
:Ans- No
13. What are you assuming by estimating q based on the frequency of ho-
mozygous recessive genotypes in the population?
:Ans- Assuming hardy weinberg
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1. Polymorphism
:Ans- the presence of genetic variation within a population, upon which
natural selection can operate
2. What are B and B in an organism's DNA?
:Ans- Represent a difference (allele or polymorphism) in the DNA sequence at a
location (locus) in the organisms genome. The dual strand composition makes it
convenient to use letters of the alphabet and capitalize one.
3. 3 factors affecting independence and F2 ratios
:Ans- Pleiotropy, epistasis, linkage
4. Pleiotropy
:Ans- one locus affects two or more traits
5. Epistasis
:Ans- alleles at one locus affect the expression of alleles at a different locus
6. Linkage
:Ans- two or more loci are on the same chromosome
7. How does W dominant allele for white cat also cause deafness?
:Ans- -
1/ 7
,Melanocytes
- produce fur pigmentation but are also present for electrical transmission to the
brain
- defective melanocyte development means no pigment or electrical signals = white
and deaf
8. How does W allele for white cat display epistasis?
:Ans- W masks all other colour and pattern genes and therefore shows dominant
epistasis, ww allows expression of colours and patterns
9. Calculating allele frequencies by counting
:Ans- separate genotypes into how many A and a alleles for each, add up for each
and divide by total # alleles
OR
p = P + 0.5H
q = Q + 0.5H
and P + H + Q = 1
where P is freq of homo dominant, H is freq of hetero and Q is freq of homo recessive
2/ 7
, 10. Hardy-Weinberg Equilibrium
:Ans- Present in a large, random mating population in the absence of migration,
mutation and selection
"Allele frequencies and genotypic frequencies remain constant and genotypic fre-
quencies are determined by allele frequencies"
11. What does it mean to say that Hardy Weinberg Equilibrium is a utopian
state?
:Ans- Most populations break some or all of the rules
12. Do p and q change with random mating?
:Ans- No
13. What are you assuming by estimating q based on the frequency of ho-
mozygous recessive genotypes in the population?
:Ans- Assuming hardy weinberg
3/ 7
