Genes in Populations - week 3

Question 1

what is the role of the animal breeder

Answer 1

to change populations, not individuals

Question 2

what is a gene frequency/ allelic frequency

Answer 2

the relative frequency of a particular allele in a population

Question 3

what is gene frequency/ allelic frequency a measure of

Answer 3

how common a particular allele is in a population

Question 4

what does the relative frequency range from

Answer 4

0-1

Question 5

what is the frequency if the allele frequency does not exist in a population

Answer 5

zero 0

Question 6

what is the frequency if it is the only allele in the population

Answer 6

one 1

Question 7

what is the frequency if it comprises 47% of the genes at locus in a population

Answer 7

the frequency is 0.47

Question 8

what does p represent

Answer 8

frequency of the dominant allele

Question 9

what does q represent

Answer 9

frequency of the recessive allelle

Question 10

what does p+q always =

Answer 10

1

Question 11

what is genotypic frequency

Answer 11

is the relative frequency of a one - locus genotype in a population

Question 12

what does P represent

Answer 12

homozygous dominant genotypic frequency

Question 13

what does H represent

Answer 13

heterozygous genotypic frequency

Question 14

what does Q represent

Answer 14

homozygous recessive genotypic frequency

Question 15

what does P+Q+H=

Answer 15

1

Question 16

what is selection?

Answer 16

selection determines which animals breed

Question 17

what is the effect of selection from a population genetic viewpoint

Answer 17

increase the frequency of favourable alleles

Question 18

what is the result of selection

Answer 18

the next generations should have better breeding values (set of genes)

Question 19

who invented Hardy weinberg equilibrium 1908

Answer 19

George Hardy - british mathematicain
Wilhelm weinbery - german physician

Question 20

what does the Hardy-Weinberg Equilibrium allow us to predict

Answer 20

the offspring genotype frequency using the parental genotype frequency

Question 21

what is the basic law of mendelian genetics

Answer 21

law of segregation

Question 22

what is the basic law of population genetics

Answer 22

hardy-Weinberg law

Question 23

(p+q)^2

Answer 23

1^2

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

Question 24

are domestic population in equilibrium

Answer 24

NO

Question 25

definition of equilibrium

Answer 25

that frequencies do not change between generations

Question 26

list 4 ways to change gene frequencies

Answer 26

1. random genetic drift
2. mutation
3. migration
4. selection - of most interest to animal breeders

Question 27

Effect of inbreeding on gene breeding

Answer 27

• increase homozygous dominant and recessive.
• decrease heterozygous genotype

Question 28

Effect of crossbreeding on gene frequency

Answer 28

increase heterozygote
- decrease homoezygote

increase genetic variation

Question 29

random genetic drift

Answer 29

• random change due to chance
• H-W assumes large populations
• we with small populations

Question 30

what reduces risk of random genetic drift

Answer 30

increasing population size

Question 31

what is effective population (Ne)

Answer 31

effective number of breeding animals
Ne = 2 x number of mating pairs

Question 32

what is the equation of effective population

Answer 32

Ne=4NmNf / (Nm+Nf)

Question 33

what is mutation

Answer 33

biochemical change in DNA sequence
u = mutation rate from A(dominant) to a (recessive)
- u=1/25,000
v = mutation rate from a to A
- v = 1/250,00

Question 34

What is migration

Answer 34

introduction of alleles from outside the population
- Natural migration
- Artificial migration eg crossbreeding

Question 35

why do animal breeding carry out selection

Answer 35

for economically important traits
- quantitative
- qualitative

Question 36

what are qualitative traits

Answer 36

controlled by single gene

Question 37

what are quantitative traits:

Answer 37

controlled by many genes