MBG 2400 Exam Review questions well
answered to pass
pleiotropy - correct answer ✔✔one locus affects 2 or more traits
ex. W allele causes white cats but also causes deafness bc melanocytes affect fur pigment and
are in inner ear - defective melanocyte means no pigment or electrical signals in ear therefore
white and deaf
epistasis - correct answer ✔✔alleles at one locus affect expression of alleles at a another locus
results in modification of 9:3:3:1 ratio
linkage - correct answer ✔✔two or more loci are on the same chromosome or are behaving like
they are
Hardy-Weinberg Equilibrium - correct answer ✔✔in a large, random mating population, in the
absence of migration, mutation, and selection (nothing changes), allele and genotypic
frequencies remain *constant* and genotypic frequencies are determined by allele frequencies
f(A) = p, f(AA) = p^2
f(a) = q, f(aa) = q^2
f(Aa) = 2pq
how to tell if a population is in H-W equilibrium? - correct answer ✔✔make sure f(AA) = p^2 = P
migration - correct answer ✔✔movement of alleles from one population to another
proportion of alleles in new population depends on immigration rate and difference in allele
frequencies b/w the 2 populations
, selection - correct answer ✔✔process that determines which individuals become the parents of
the next generation
2 types: natural selection and artificial selection
natural selection - correct answer ✔✔environment decides
adapt to environment or perish
- evolution (subtle pressure) ex. changes in beak shape in finches depending on what type of
food they ate
- bottlenecks (moderate pressure) -> population goes through extreme tests of survivial, then
pressure reduces ex. cheetahs
- extinction (massive pressure) ex. dinosaurs
artifical selection - correct answer ✔✔humans decide
goal oriented (appearance, use, productivity, satisfaction, whimsy, etc.)
qualitative traits - correct answer ✔✔controlled by one or a few loci
discrete phenotypes
ex. eye colour, seed texture, blood type, colour blindness
quantitative traits - correct answer ✔✔controlled by multiple loci - also called polygenic traits
(many genes)
usually continuous phenotypes
ex. height, weight, milk yield, temperament
some have more discrete phenotypes/categories aka threshold traits
ex. calving ease can be judged based on it being unassisted, easy pull, hard pull, or surgical
variance - correct answer ✔✔measure of how much variability there is within a population for a
certain trait
answered to pass
pleiotropy - correct answer ✔✔one locus affects 2 or more traits
ex. W allele causes white cats but also causes deafness bc melanocytes affect fur pigment and
are in inner ear - defective melanocyte means no pigment or electrical signals in ear therefore
white and deaf
epistasis - correct answer ✔✔alleles at one locus affect expression of alleles at a another locus
results in modification of 9:3:3:1 ratio
linkage - correct answer ✔✔two or more loci are on the same chromosome or are behaving like
they are
Hardy-Weinberg Equilibrium - correct answer ✔✔in a large, random mating population, in the
absence of migration, mutation, and selection (nothing changes), allele and genotypic
frequencies remain *constant* and genotypic frequencies are determined by allele frequencies
f(A) = p, f(AA) = p^2
f(a) = q, f(aa) = q^2
f(Aa) = 2pq
how to tell if a population is in H-W equilibrium? - correct answer ✔✔make sure f(AA) = p^2 = P
migration - correct answer ✔✔movement of alleles from one population to another
proportion of alleles in new population depends on immigration rate and difference in allele
frequencies b/w the 2 populations
, selection - correct answer ✔✔process that determines which individuals become the parents of
the next generation
2 types: natural selection and artificial selection
natural selection - correct answer ✔✔environment decides
adapt to environment or perish
- evolution (subtle pressure) ex. changes in beak shape in finches depending on what type of
food they ate
- bottlenecks (moderate pressure) -> population goes through extreme tests of survivial, then
pressure reduces ex. cheetahs
- extinction (massive pressure) ex. dinosaurs
artifical selection - correct answer ✔✔humans decide
goal oriented (appearance, use, productivity, satisfaction, whimsy, etc.)
qualitative traits - correct answer ✔✔controlled by one or a few loci
discrete phenotypes
ex. eye colour, seed texture, blood type, colour blindness
quantitative traits - correct answer ✔✔controlled by multiple loci - also called polygenic traits
(many genes)
usually continuous phenotypes
ex. height, weight, milk yield, temperament
some have more discrete phenotypes/categories aka threshold traits
ex. calving ease can be judged based on it being unassisted, easy pull, hard pull, or surgical
variance - correct answer ✔✔measure of how much variability there is within a population for a
certain trait
