G16-17

Question 1

what is genetic variation

Answer 1

described in terms of no. of allelss at gene loci and there frequencies
evolution = change in allele freq between generation

Question 2

what is a population

Answer 2

a group of potentially interbreeding individuals in a given area

Question 3

what are allozymes/alloenzymes

Answer 3

variant forms of an enzyme coded for by different alleles at the same locus.
- allow heterozygotes to be distinguished from homos
usually assumed to be neutral

Question 4

how can you calculate allele frequency for N individuals

Answer 4

calculated from the observed no. of each genotype

= 2Xno. AA + no (Aa) / total

Question 5

what are the assumptions of the HWE

Answer 5

no overlapping generations
equal sex ratio
no gene flow(migration/emigration)
random mating
no selection
no mutation
infinitely large pop (no random genetic drift

Question 6

what are the sexes in birds and butterlifes

Answer 6

ZZ = males
ZW = females

Question 7

what is the wahlund effect

Answer 7

reduction in heterozygosity due to formation of sub populations

Question 8

what are the 4 major causes for deviation from HWE and variation between populations

Answer 8

mutation - back mutation rarer
selection - survivorship reproduction differences
random genetic drift - random sampling
migration - gene flow immigration/emigration

Question 9

what is the mutation rate `

Answer 9

mu u

Question 10

what is the p’ freq if mutation rate is mu

and what does it assume

Answer 10

p - up

assumes back mutation is negligable

Question 11

what is change in alelle frequency after t generations with mutation rate mu

Answer 11

pt= pe^-ut0

again negligble back mutation

Question 12

what is the fitness

Answer 12

the contribution of a phenotype/genotype to the next generation

Question 13

what is absolute fitness

Answer 13

actual no. of viable offspring a pheno/genotype leaves on average

Question 14

what is the strength of selection/selection coefficient (s)

Answer 14

proportionate reduction in fitness relative to standard

Question 15

what would be the relative fitness of individuals with AA 8/10 Aa 8/10 and aa 6/10 survival to adulthood

Answer 15

1
1
0.75 so s = 1-0.75 = 0.25 so (1-s)

Question 16

how do you calculate the mean fittness of a population W

Answer 16

sum of the surviving adult genotypes after selection

so add in the selection to those selected against

Question 17

what did the experiment on Culex pippiens insecticde resistance show
what is this an example of

Answer 17

• chloryfiros interferes with function of Acetylcholinesterase
  Ace^R gives immunity to chloryfiros insecticide
  over 22 years in exposed and non exposed showed that Ace^R freq increased
  also did control for asparate amino transferase 1 not involved in insecticide resistence showed freq didnt change between pops
  directional selection

Question 18

what is balancing selection

Answer 18

when allele is not advantageous in all situations so more than one allele is maintainted in the population
eg. allele adv in heterozygotes relative to homo or advantageous when rare eg. sickle cell

Question 19

what is purifying selection

Answer 19

disadvantageous mutations removed as they arrise

Question 20

what is non random mating the types

Answer 20

dissortative - unlike individuals mate
assortative mating - like individs mate
inbreeding - needs reference pop - more likely to inbreed than chance

Question 21

what is the expected heterozygosity in random mating

Answer 21

2pq

Question 22

what does it mean if H0

Answer 22

deficit of heteros and excess homos due to inbreeding

Question 23

what does it mean if H0=HE

Answer 23

no deficit of heteroz no inbreeding random mamting in HWE F =0

Question 24

what does it mean if H0>HE

Answer 24

outbreeding inbreeding avoidance.