Microevolution

Question 1

microevolution def

Answer 1

changes in gene pool of populations over time

Question 2

gene pool def

Answer 2

all alleles of all genes of all individuals in a population

Question 3

how is macroevolution different from micro

Answer 3

evolution on a grander scale

major evolutionary events above level of the species

includes speciation

microevolution is within a species

Question 4

why is population genetics ikmportant

Answer 4

combines darwins theory of evolution with mendel’s theory of inheritance

Question 5

what does pop genetics say about human pathoegns

Answer 5

bacteria - shows resistance to antibiotics (MRSA)

viruses - resistance to antiviral (HIV)

new pathogens e.g. ebola, corona, influenza (has had many variants e.g. spanish flue, swine flu, bird flu etc.)

Question 6

covid19 -when was most recent common ancestor?

Answer 6

shown via molecular clock

Nov 2019 - lines up w/ first outbreak in wuhan china

Question 7

which coronavirus is SARS CoV 2 related to

Answer 7

beta corona viruses

found in bats

Question 8

how is sars cov 2 related to the virus found in horseshoe bats

Answer 8

96% the same
shows not directly the same as the one in bats, so virus diverged ~ 40-70 yrs ago

Question 9

why might thalssemia diseases be common in certain areas?

Answer 9

heterzygous form gives resistance to malarial parasite

so its commonality overlaps in places where malaria common

similar to sickle cell’s malarial resistance

Question 10

importance of pop genetics in wild populations

Answer 10

important to know how much genetic diversity is in population and how it’s distributed

low diversity not good (e.g. in cheethah)

Question 11

how many genotypes in a single gene locus in diploid organism

Answer 11

3 genotypes: RR, Rr and rr

Question 12

how do we calculate allele frq?

Answer 12

no. of allele of one type/total no. of alleles

Question 13

what does p and q represent

Answer 13

p = dominant
q= recessive

Question 14

how do we calculate genotype frq

Answer 14

no. indivudals of one genotype/total no. individuals

Question 15

hardy weinburg equilibrium equation

Answer 15

shows the relation between allele frq and genotype frq

p^2 + 2pq + q^2 = 1

p+q = 1 always

Question 16

what are the conditions that need to be met for the HW equilibrium to be kept

Answer 16

• large population size
• random mating
• no migrating from other pops
• no selection
• no mutation (mutation rate low, but usually not significant unless there’s selection so dw bout it)

Question 17

what factors could change allele frq

Answer 17

genetic drift (large effects on small pop)

non-random mating - sexual selection

migration - transfer of alleles from one pop to another

selection

Question 18

how is genetic variation preserved? - natural selection

Answer 18

via balancing selection:
- heterozygotic advantage (e.g. sickle cell and malarial resistance)
- diploidy
- neutral alleles

also diff selective pressures across geographic range of pop = clinal variation

Question 19

what has lead to lack of genetic diversity and low populations in cheetahs?

Answer 19

poor sperm quality
low fecundity
high susceptibility to infection

Question 20

what is the mating beh in cheetahs and how was this experimentally shown?

Answer 20

one female will mate with multiple males

DNA samples obtained non-invasively (from their poo) from mother and cubs
did paternity test
found that 43% of litters father by more than one male

mostly the female wouldn’t go back to baby daddy in subsequent years

POLYANDRY - females w/ multiple males

Question 21

pros and cons of polyandry for female cheethas

Answer 21

cons:
inc risk of predation
meeting aggressive males
higher chance of catching disease

pros:
gives inc genetic diversity in offspring
avoids infanticide (common in other big cats)

Question 22

why might genetic disease be more common in isolated populations?

Answer 22

founder effects and subsequent genetic drift
deletrious alleles may become more common
effects are more pronounced in smaller populations

Question 23

what is diploidy

Answer 23

is the harmful allele is recessive, then selection acts on homo recessive genotype only

but the allel stays in the population via the heterozygous form
effectively hidden from selection