10 POPULATION GENETICS Flashcards
(54 cards)
1
Q
- Members of a species can interbreed & produce fertile offspring
A
Gene Pool
2
Q
____ have a shared gene pool
A
species
3
Q
- all of the alleles of all individuals in a population
A
Gene Pool
4
Q
- Different species ____ exchange genes by interbreeding
A
do NOT
5
Q
- Different species that interbreed often produce ____
example?
A
sterile or less viable offspring
e.g. mule
6
Q
- A group of the same species living in an area
A
population
7
Q
- Formation of new species
- One species may split into 2 or more species
- Requires very long periods of time
A
speciation
8
Q
- Combines Darwinian selection and Mendelian inheritance
A
Modern Synthesis Theory
9
Q
study of genetic variation within a population
A
- Population genetics
10
Q
MST emphasizes on ____
A
quantitative characters (height, size …)
11
Q
- 1940s – comprehensive theory of evolution
A
Modern Synthesis Theory
12
Q
who introduced MST
A
Fisher & Wright
13
Q
- Recognizes that ____ are responsible for the inheritance of characteristics
A
GENES
14
Q
- Recognizes that ____, not ____, evolve due to natural selection & genetic drift
A
POPULATIONS
individuals
15
Q
- Recognizes that SPECIATION usually is due to the ____ of small genetic changes
A
gradual accumulation
16
Q
- The modern synthetic theory of evolution describes the evolution in terms of ____ in a population that leads to the formation of a new species.
A
genetic variations
17
Q
- Changes occur in gene pools due to mutation, natural selection, genetic drift, etc.
A
Microevolution
18
Q
- Gene pool changes cause more ____ in individuals in the population.
Example?
A
VARIATION
Bacteria becoming unaffected by antibiotics (resistant)
19
Q
- the process of heredity in a random mating population does not change either allelic frequencies or genotypic frequencies at a given locus
A
Hardy-Weinberg Principle
20
Q
Hardy-Weinberg Principle used to describe a?
A
non-evolving population
21
Q
HWP
- Shuffling of alleles by meiosis and random fertilization have ____ on the overall gene pool
A
no effect
22
Q
- ____ are NOT expected to actually be in Hardy-Weinberg equilibrium
A
Natural populations
23
Q
- Deviation from Hardy-Weinberg equilibrium usually results in ____
A
evolution
- Understanding a non-evolving population, helps us to understand how evolution occurs
24
Q
5 Assumptions of the H-W Principle
A
- large population size
- no migration
- no net mutations
- random mating
- no natural selection
25
Traits selected for random mating
mimicry
color
26
The gene pool of a NON-EVOLVING population remains ____ over multiple generations
CONSTANT
27
The Hardy-Weinberg Equation:
1.0 = p2 + 2pq + q2
## Footnote
p2 = frequency of AA genotype
2pq = frequency of Aa
q2 = frequency of aa genotype
28
Allele Frequency using Hardy-Weinberg
1.0 = p + q
## Footnote
p = frequency of A allele
q = frequency of a allele
29
5 Causes of Microevolution
1. genetic drift
2. natural selection
3. gene flow
4. mutation
5. non-random mating
30
the change in the gene pool of a small population due to chance
genetic drift
31
success in reproduction based on heritable traits results in selected alleles being passed to relatively more offspring (Darwinian inheritance)
- Cause ____ of Populations
natural selection
ADAPTATION
32
is genetic exchange due to the migration of fertile individuals or gametes between populations
gene flow
33
a change in an organism’s DNA; can be transmitted in gametes to offspring
mutation
34
Mates are chosen on the basis of the best traits
non-random mating
35
2 Factors that Cause Genetic Drift
bottleneck effect
founder effect
36
- a drastic reduction in population (volcanoes, earthquakes, landslides …)
- Reduced genetic variation
bottleneck effect
37
In bottleneck effect, ____ population may not be able to adapt to new selection pressures
Smaller
38
- occurs when a new colony is started by a few members of the original population
- Reduced genetic variation
* Founder Effect
39
May lead to speciation
founder effect
40
example of
Loss of Genetic Variation
* Cheetahs have little genetic variation in their gene pool
## Footnote
* This can probably be attributed to a population bottleneck they experienced around 10,000 years ago, barely avoiding extinction at the end of the last ice age
41
3 Modes of Natural Selection
1. directional selection
2. disruptive selection
3. stabilizing selection
42
- Favors individuals at one end of the phenotypic range
* Directional Selection
43
- Most common during times of environmental change or when moving to new habitats
* Directional Selection
44
- Favors extreme over intermediate phenotypes
* Disruptive selection
45
- Occurs when environmental change favors an extreme phenotype
* Disruptive selection
46
- Favors intermediate over extreme phenotypes
* Stabilizing Selection
47
- Reduces variation and maintains the current average
* Stabilizing Selection
48
human birth weight is an example of what mode of natural selection? and how?
stabilizing selection
## Footnote
if high, obesity
if low, malnourish
49
5 variations in populations
* geographic variations
* hetezogote advantage
* mutations
* genetic recombination
* co-evolution
50
* Mutations
-In stable environments, mutations often result in little or no benefit to an organism, or are often harmful
-Mutations are more beneficial (rare) in changing environments
example?
HIV resistance to antiviral drugs
51
source of most genetic differences between individuals in a population
genetic recombination
52
Often occurs between parasite & host and flowers & their pollinators
co-evolution
53
* Favors heterozygotes (Aa)
* Maintains both alleles (A,a) instead of removing less successful alleles from a population
heterozygote advantage
54
example of heterozytote advantage
* Sickle cell anemia
## Footnote
o Homozygotes exhibit severe anemia, have abnormal blood cell shape, and usually die before reproductive age.
o Heterozygotes are less susceptible to malaria
