Genetics and Animal breeding deck 1 Flashcards
Define a population.
a group of individuals of one species that inbreed in the
same place, at the same time, and are isolated from other groups of the same species.
A “basic unit of evolution”.
A term for an association of different organisms forming a closely integrated community.
biocoenosis
A species becomes separated into distinct populations due to what key factors that drive evolution?
genetic variation between individuals,
natural selection,
isolation.
term for random mating
panmixia / panmixis
When is a population referred to as closed?
mating with individuals from other populations
does not occur
define gene pool
The sum total of all alleles (collective genetic information) carried in all members of a population.
what is population size denoted as?
N
what is a sample of a population denoted as?
n
another term for random
stochastic
The probability of an event is a ratio that is given as?
a numerical value between zero and one.
The probability of a sure event is?
1
The probability of an impossbile event is?
0
What is the multiplication rule?
Given the probabilities of two independent events (A and B), the rule states that the probability that both events occur is found by multiplying the probabilities of the events.
p(AB) = p(A) x p(B).
How are different genotype-numbers denoted?
D
H
R
How are genotype frequencies denoted?
d
h
r
How is d calculated?
d = D/N
How is h calculated?
h = H/N
How is r calculated?
r = R/N
d + h + r = ?
always 1
The sum of genotype frequencies always equals?
1
Based on what info can absolute counts of alleles in the
population be calculated
Based on the numbers of individuals with different genotypes
What does P denote?
absolute count of dominant allele
What does Q denote?
absolute count of recessive allele
How is absolute count, P calculated?
P = 2D + H
How is absolute count, Q calculated?
Q = 2R + H
How is frequency of recessive allele denoted?
q
How is frequency of dominant allele denoted?
p
What is the Hardy-Weinberg principle?
the concept that in a panmictic population in genetic equilibrium - gene and genotype frequencies will remain constant from generation to generation.
What is the Hardy-Weinberg formula/equation?
p2 + 2pq + q2 = 1
where
p2 is BB
2pq is Bb
q2 is bb
direct mutation is?
Change of the allele from normal to mutant
reverse mutation is?
change of the mutant allele to normal
The frequency of direct mutations is typically
designated by the letter
u
The frequency of reverse mutations is typically
designated by the letter
v
Define mutability
is the mutation rate of genes.
The mutability of genes varies between different loci.
what is mutation pressure
the intensity of the occurrence of mutations
What is mutation pressure dependent on?
the ratio between of the direct and reverse mutations in a
population.
Selection coefficient (s) is?
a measure of the relative reduction in the contribution a particular genotype makes as compared with another genotype in the population.
If one of the three genotypes (AA, Aa, aa) is completely removed from a generation, this genotype has a selection coefficient of?
s = 1
in case of the maximum relative contribution of a genotype to the next generation (none of the animals
possessing a given genotype have been removed), the selection coefficient would be?
s = 0
What does W denote
the selection value or fitness of all the remaining animals is expressed by W
selection efficiency (Δq) is?
The change in gene frequency in the next generation
selection efficiency indicates
the rate of improvement in performance (removal of undesirable genes) from selection during a generation.
define random gene drift
the change in the frequency of an existing gene variant in a population due to random chance.
define the concept of effective population size
The number of individuals that effectively participates in producing the next generation