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Flashcards in G16-17 Deck (24):
1

what is genetic variation

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

2

what is a population

a group of potentially interbreeding individuals in a given area

3

what are allozymes/alloenzymes

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

4

how can you calculate allele frequency for N individuals

calculated from the observed no. of each genotype
= 2Xno. AA + no (Aa) / total

5

what are the assumptions of the HWE

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

6

what are the sexes in birds and butterlifes

ZZ = males
ZW = females

7

what is the wahlund effect

reduction in heterozygosity due to formation of sub populations

8

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

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

9

what is the mutation rate `

mu u

10

what is the p' freq if mutation rate is mu
and what does it assume

p - up
assumes back mutation is negligable

11

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

pt= pe^-ut0
again negligble back mutation

12

what is the fitness

the contribution of a phenotype/genotype to the next generation

13

what is absolute fitness

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

14

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

proportionate reduction in fitness relative to standard

15

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

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

16

how do you calculate the mean fittness of a population W

sum of the surviving adult genotypes after selection
so add in the selection to those selected against

17

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

- 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

18

what is balancing selection

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

19

what is purifying selection

disadvantageous mutations removed as they arrise

20

what is non random mating the types

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

21

what is the expected heterozygosity in random mating

2pq

22

what does it mean if H0

deficit of heteros and excess homos due to inbreeding

23

what does it mean if H0=HE

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

24

what does it mean if H0>HE

outbreeding inbreeding avoidance.