Population Genetics

Question 1

what are the 4 main evolutionary processes?

Answer 1

natural selection
genetic drift
mutation
gene flow

Question 2

what is a sexual population?

Answer 2

set of organisms in which any pair of members can breed - implies all members belong to the same species and live near e/o

Question 3

how does evolution occur?

Answer 3

when there are changes in the frequencies of alleles w/in a population

Question 4

what is the Hardy-Weinberg principle?

Answer 4

frequency of alleles will remain constant in the absence of selection, mutation, migration and genetic drigt

Question 5

what is Hardy-Weinberg equilibrium?

Answer 5

refers to the stability of allele frequencies over time

Question 6

how do you determine genotype frequency?

Answer 6

take the number of members with the genotype and divide by the entire population

Question 7

what is the Hardy-Weinberg Equilibrium equation?

Answer 7

(p+q)^2 = p^2 +2pq+q^2 = 1
p= frequency of allele A
q = frequency of allele a
p^2 = frequency of individual AA
q^2= frequency of individual aa
2pq = the frequency of individual Aa

Question 8

how does natural selection work?

Answer 8

acts upon genetic variation by increasing the frequencies of alleles that promote survival or fertility and reducing the frequency of alleles that cause dz

Question 9

do dominant dz alleles occur more or less frequently?

Answer 9

less frequently! it is more readily exposed to the effects of natural selection and therefore are weeded out

Question 10

are recessive dz alleles more or less frequent?

Answer 10

more frequent as they are typically hidden in heterozygotes

may stick around b/c may confer an advantage

Question 11

what are some recessive dzs that confer an advantage when person is heterozygous for it?

Answer 11

sickle cell - malaria
cystic fibrosis - typhoid fever
hemochromatosis - iron poor environments
G-6-PD deficiency - malaria
hemolytic anemia - malaria

Question 12

what type of mutation is potentially harmful for the individual?

Answer 12

point mutation - 70% of these kinds of mutations have damaging effects and the remainder are either neutral or weakly beneficial

Question 13

what is the founder effect?

Answer 13

novel gene production through duplication and mutation of an ancestral gene

Question 14

what is genetic drift?

Answer 14

some individuals, by chance, may leave behind more descendants than others and thus propagate their genes

Question 15

what causes genetic drift?

Answer 15

change in allele frequency caused by random sampling

may cause gene variants to disappear completely and thereby reduce genetic variability

Question 16

what did Motoo Kimura theorize?

Answer 16

most instances where a genetic change spreads across a population are caused by genetic drift

Question 17

what is gene flow? what does it result in?

Answer 17

exchange of genes btw populations which are usually of the same species
results in: populations that are close to each other geographically often tend to have similar gene frequencies

Question 18

how does gene flow and transfer work?

Answer 18

intro or loss of genes into a population through immigration or emigration of individual organisms btw established populations

Question 19

what is reproductive isolation?

Answer 19

when isolation occurs two populations are able to diverge so as to create a new species
gene flow may slow this process by spreading genetic differences btw the populations

Question 20

what is gene flow hindered by?

Answer 20

hindered by mountain ranges, oceans, deserts and even man-made structures