BIOB51 MIDTERM EXAM REPORTED
QUESTIONS WITH 100% CORRECT
ANSWERS
Polyphenic trait - Answer- single genotype produces multiple phenotypes depending on
environment
Population genetics - Answer- Study of the distribution and frequencies of alleles in
populations
- Study of how & why allele frequencies change
Population - Answer- A group of interacting and potentially interbreeding individuals of
the same species
Genetic locus - Answer- location of a specific gene or sequence of DNA on a
chromosome
Homozygous - Answer- Individual carries 2 copies of the same allele at a locus
Heterozygous - Answer- Individual carries different alleles at a locus
Evolution - Answer- change in allele frequencies in a population over time
Hardy-Weinberg Theorem - Answer- The principle that frequencies of alleles and
genotypes in a population remain constant from generation to generation, provided that
only Mendelian segregation and recombination of alleles are at work.
Hardy-Weinberg equilibrium - Answer- Population is infinitely large
Genotypes do not confer differences in fitness
No mutation
Mating is random
No migration
Mutation - Answer- Main source of genetic variation
- CREATES variability
Migration - Answer- Movement of alleles between populations
Drift - Answer- Chance disappearance of alleles
Selection - Answer- Differential survival and reproduction
, Bottleneck - Answer- Results in non-representative set of alleles for subsequent
populations, even after population size rebounds
Founder effect - Answer- Type of bottleneck resulting from a small number of individuals
colonizing a new, isolated habitat
Fitness - Answer- Survival and reproductive success of an individual with a particular
phenotype
Relative fitness (w) - Answer- Fitness of individuals with one genotype compared with:
- The average fitness of the population
OR
- The most fit genotype
Pleiotropy - Answer- Multiple phenotypic traits associated with a single gene
Antagonistic pleiotropy - Answer- Beneficial effects for one trait but detrimental effects
for the other trait
Negative selection - Answer- Experienced by alleles that lower fitness
Positive selection - Answer- Experienced by alleles that increase fitness
- faster evolution than synonymous sites indicates this
Additivity - Answer- effects of alleles can be predicted by summing the number of copies
that are present
Dominance - Answer- Dominant allele masks presence of recessive allele in
heterozygote
Negative frequency-dependent selection - Answer- Common phenotypes are selected
against, and rare phenotypes are favoured
Heterozygote advantage - Answer- Heterozygosity confers greater fitness than
homozygotes
Quantitative genetics - Answer- Study of the genetic mechanisms and evolution of
continuous phenotypic traits
Linkage equilibrium - Answer- Exists if the occurrence of an allele at one locus is
independent of the presence or absence of an allele at a second locus
Linkage disequilibrium - Answer- Exists if the occurrence of an allele at one locus is
non-randomly associated with the presence or absence of an allele at a second locus
QUESTIONS WITH 100% CORRECT
ANSWERS
Polyphenic trait - Answer- single genotype produces multiple phenotypes depending on
environment
Population genetics - Answer- Study of the distribution and frequencies of alleles in
populations
- Study of how & why allele frequencies change
Population - Answer- A group of interacting and potentially interbreeding individuals of
the same species
Genetic locus - Answer- location of a specific gene or sequence of DNA on a
chromosome
Homozygous - Answer- Individual carries 2 copies of the same allele at a locus
Heterozygous - Answer- Individual carries different alleles at a locus
Evolution - Answer- change in allele frequencies in a population over time
Hardy-Weinberg Theorem - Answer- The principle that frequencies of alleles and
genotypes in a population remain constant from generation to generation, provided that
only Mendelian segregation and recombination of alleles are at work.
Hardy-Weinberg equilibrium - Answer- Population is infinitely large
Genotypes do not confer differences in fitness
No mutation
Mating is random
No migration
Mutation - Answer- Main source of genetic variation
- CREATES variability
Migration - Answer- Movement of alleles between populations
Drift - Answer- Chance disappearance of alleles
Selection - Answer- Differential survival and reproduction
, Bottleneck - Answer- Results in non-representative set of alleles for subsequent
populations, even after population size rebounds
Founder effect - Answer- Type of bottleneck resulting from a small number of individuals
colonizing a new, isolated habitat
Fitness - Answer- Survival and reproductive success of an individual with a particular
phenotype
Relative fitness (w) - Answer- Fitness of individuals with one genotype compared with:
- The average fitness of the population
OR
- The most fit genotype
Pleiotropy - Answer- Multiple phenotypic traits associated with a single gene
Antagonistic pleiotropy - Answer- Beneficial effects for one trait but detrimental effects
for the other trait
Negative selection - Answer- Experienced by alleles that lower fitness
Positive selection - Answer- Experienced by alleles that increase fitness
- faster evolution than synonymous sites indicates this
Additivity - Answer- effects of alleles can be predicted by summing the number of copies
that are present
Dominance - Answer- Dominant allele masks presence of recessive allele in
heterozygote
Negative frequency-dependent selection - Answer- Common phenotypes are selected
against, and rare phenotypes are favoured
Heterozygote advantage - Answer- Heterozygosity confers greater fitness than
homozygotes
Quantitative genetics - Answer- Study of the genetic mechanisms and evolution of
continuous phenotypic traits
Linkage equilibrium - Answer- Exists if the occurrence of an allele at one locus is
independent of the presence or absence of an allele at a second locus
Linkage disequilibrium - Answer- Exists if the occurrence of an allele at one locus is
non-randomly associated with the presence or absence of an allele at a second locus
