lecture 10

Question 1

what is epistasis

Answer 1

2 genes can have epistatic relationship = interact to determine phenotype

Question 2

describe population genetics

Answer 2

moving from a few organisms to whole populations = new genetic properties and forces emerge
bc enormous genotype an d they change over time

Question 3

describe emergent population level properties and processes - 3

Answer 3

genotype and allele frequencies
Change in genotype and allele frequencies - over time= evolution
population to population variation - variations between populations in genotype and allele frequencies

Question 4

describe emergent population genetic level forces

Answer 4

things cause evolutionary change = change allele and genotype frequencies
change in population level variation due to many factors

Question 5

what can a change in population level variation be due to - 4

Answer 5

mutation
migration
selection
chance = genetic drift

Question 6

describe frequency of the b blood type across a geographical region - from mendelian genetics to population genes - ex of phenomena

Answer 6

frequency low in spain and portugal and as move to central europe frequency increases

Question 7

describe frequency of the adh(F) allele over time - from mendelian genetics to population genes - ex of phenomena

Answer 7

one allele of gene = becomes fast allele when flies raised on increased amounts of ethanol = could be due to detoxification of ethanol
nothing happened to the control

Question 8

describe single gene - allele frequency of sickle cell anemia - from mendelian genetics to population genes - ex of phenomena

Answer 8

sickle cell anemia = when a person has 2 copies of the HbS allele
interferes with circulation and physiology
when one copy = heterozygous = advantage against malaria

Question 9

describe population level variation - ex setup

Answer 9

dna sequences in sample, n=7 individuals of a population
variation in single nucleotide polymorphisms (SNPs), indels, microstallites

Question 10

what are microstallites

Answer 10

repeats of agag

Question 11

describe population level variation - ex results

Answer 11

results = 1-3 have more than 4-7
sequence data = small fraction of genome
can see variations
some segregation of allales or nts, indels = missing part of sequence

Question 12

what is haplotype variationn

Answer 12

bp 1-35 on chrom 22
not all individuals have same for this chrom = haplotype

Question 13

what can haplotype variation tell us about + ex

Answer 13

history of population
migration looks to be stepwise for post glacial recolonization
diff parts = have diff amounts of mutations
see history of migration

Question 14

what do genetics at the population level concentrates on

Answer 14

concentrates on collections of individuals and their genetic properties
especially frequencies of alleles, genotypes, haplotypes in time and space (geography, habitats), snps = single nt polymorphisms

Question 15

what do genetics at the population level study

Answer 15

studies origin, maintenance and change of allelic and genotypic variation in populations

Question 16

what does genetics at the population level makes use of

Answer 16

makes use of models to study processes that influence population genetic composition and make predictions about how it will change - in response to selection, migration
theory heavy
abstract way to think about it - predictions

Question 17

describe gene pool model

Answer 17

populations do not actually have hard boundaries

Question 18

describe characterizing the gene pool

Answer 18

count alleles of each type
genotype frequencies = AA, Aa, aa (number of each/total people)
alelle frequencies = A and a (alleles/total alleles)

Question 19

notation for genotype frequencies

Answer 19

for a gene with 2 alleles, A and a
frequency genotypes = fAA, fAa or faa
the sum of fAA + fAa + faa = 1.00

Question 20

notation for genotype frequencies

Answer 20

for gene with 2 alleles - biallelic loci
frequency of allele 1 - A = p
frequency of allele 2 - a = q
since p+q = 1 then q=p-1 since must sum to one

Question 21

describe population genetic variance - blood groups locus 2 major alleles, MN

Answer 21

codominance = heterozygous both show up
2 alleles = antigens on blood cells
use reactions since alleles wont work

Question 22

how to go from genotype to allele frequency

Answer 22

p=fMM + 1/2 fMN
q = fNN +1/2 fMN

Question 23

Can we calculate genotype frequencies in the next generation if we only know the allele frequencies in the current generation?

Answer 23

yes and no
but yes = must conform to some conditions
HARDY WEINBERG

Question 24

when can we calculate genotype frequencies in the next generation if we only know the allele frequencies in the current generation

Answer 24

if there is random mating (with respect to this locust), no mutation, no selection, no migration (isolated enough) and no drift
assume very large population and no small population effects
rate of mutant slow - since unlikely to mutate nts

Question 25

what are frequencies if hardy weinberg

Answer 25

freq AA = p^2
freq Aa = 2pq
freq aa = q^2

Question 26

describe hard weinberg proportions

Answer 26

When there is random mating, no mutation, no selection, no migration and no drift, the genotype frequencies in the next generation are frequencies OF simple punnet square with 2 hetero

Question 27

will hardy weingberg last

Answer 27

the frequencies will remain unchanged provided there is continued random mating and absence of evolutionary forces
only need single gen of hardy weinberg then will continue to hold as conditions hold

Question 28

what is dna fingerprinting

Answer 28

application of hardy weinberg
friend of the innocent
genotyping suspects at many loci (not single, tend to be snps or microsatellite alleles) each assumed to show genotype frequencies predicted by hardyweinberg theory

Question 29

general formula - hardy weinberg

Answer 29

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