Dr. Riley #1 Exam Flashcards
1
Q
Gregor Mendel
A
Reductionist
2
Q
Gregor Mendel
A
Statistical—Model System (peas)
3
Q
Was broadly interested in science
A
Mendel
4
Q
Developed life long interest in heredity and meteorology as a university student
A
Mendel
5
Q
Conducted thousands of crosses which, taken together, provided strong evidence for his principles
A
Mendel
6
Q
Easy to maintain
- small scale
- few requirements
A
Model System (peas)
7
Q
higher reproductive output
A
higher samples
8
Q
Peas are easier to manipulate because…
A
self-fertilize
cross-fertilize
9
Q
Dichotomous traits
A
either or—
Blending inheritance–never got intermediate
10
Q
inheritance of a single trait
A
Mendel’s first experiments involved crossing pure lines that differed in just one trait
11
Q
P-
A
parental generation
12
Q
parental generation
A
P
13
Q
F1-
A
offspring of P- first filial
14
Q
offspring of P- first filial
A
F1
15
Q
F2
A
F1 self-fertilizes-2nd filial
16
Q
F1 self-fertilizes-2nd filial
A
F2
17
Q
particulate inheritance
A
something passes unchanged through F1
18
Q
hereditary determanents
A
genes
19
Q
particles are independent of parent
A
recessive-disappear in F1
dominance- always show
20
Q
gene
A
a stretch of DNA that codes for a functional RNA
21
Q
Allele
A
specific version of a gene
22
Q
Genotype
A
alleles an individual carries—-SS, Ss
23
Q
Phenotype
A
how an individual looks
24
Q
Uppercase
A
Dominant
25
Lowercase
Reccessive
26
SS
homozygous
27
Ss
heterozygous
28
"recessive" - pure breeding
1/3 pure breeding
| 2/3 "hybrids"
29
each parent 1/2 to offspring
parents 2 genes---sperm/egg have 1 for every trait
30
gametes
segregation of alleles
31
Monohybrid cross
1: 2:1 Genotypic ratio
3: 1 Phenotypic ratio
32
mono
1 hybrid- contrasting/pure breeding
33
F1
all heterozygous
| all dominant phenotype
34
F2
both F1 have both--2 kinds of gametes
35
Test Cross
genotypic ratio= phenotypic ratio
36
Test Cross
1:1 if the unknown is hetero
| ALL dominant phenotype is unknown is homo
37
test cross
unknown genotype
| dominant phenotype
38
Autosomal
both male and female
39
dominant show up
every generation, even one copy BB,Bb
40
Recessive
skip generations, bb
41
X-linked
Dominant or Recessive
42
Y-linked
only males
father to ALL
son-doesn't skip generation
43
XY
dad
44
XX
mom
45
Test cross
two possible outcomes
46
0_ x oo
Test cross
47
P1
all orange offspring (dominant)
48
P2
1:1 orange * white (dominant to recessive)
49
Gene pools
contain all the alleles in a population
50
p+q=1
Hardy-Weinburg Model
51
In the absence of evolutionary forces
allele frequencies remain the same, generation to generation
52
alleles should NOT change
p or q
53
p
1 allele= dominant
54
q
1 allele= recessive
55
Genotype frequencies are the products of allele frequencies
two p's = p^2
two q's = q^2
p and q = 2pq
56
p^2 + 2pq + q^2 = 1
homo dominant + hetero + homo recessive = ALL
57
Hardy - Weinburg Equation
Determining the frequency of the recessive allele
58
the probability of getting a recessive allele from either parent is---
the frequency of the allele in the population
59
the probability of getting TWO recessive alleles is the product of--
the probability of getting one form each parent
60
We can count the number of individuals that got a recessive allele from both parents
HWE
61
Assumptions of the HW model
the HW principle states
- allele frequencies (p & q) remain the same
- genotypic frequencies are the product of allele frequencies (p^2, 2pq, & q^2)
- based on the assumptions
62
If 4% of the population can wiggle ears, what is the frequency of the recessive allele? What is the carrier frequency in this population?
```
wigglers- 4%
q^2 = 0.04
q = 0.20
2pq = 0.32
p = 0.8
```
63
The HW principle states-
```
allele frequencies (p & q) remain the same
genotypic frequencies are the product of allele frequencies (p^2, 2pq, q^2)
```
64
HW principle is based on the assumptions of:
=null
| ---no evolution
65
Biology Evolution--HW
change in [allele frequencies] in a [population over time]
66
HWE=null=no evolution if--
1. very large population
2. no mutation
3. random mating
4. no gene flow
5. selection
67
mutation (in gene)
evolution
68
A------> a
loss of function
69
A1------->
A2
70
Impact minor in populations
- lethal or deleterious
- recessive
- random
- raw material for natural selection
71
Non random mating
peas
72
Non- random mating
| Peas
- inbreeding=extreme non-random mating (selfing)
| - reduces heterozygosity (by itself)
73
(no) =/= evolution
by itself
74
expose rare
deleterious mutations
75
deleterious mutations
lower fitness
76
Fitness
relative proportion of your contribution to next generation
77
no gene flow
genetic rescue
| out-breeding depression
78
selection
heritable(alleles) variation (diff.) ----> differential
| survival and reproduction
79
Natural Selection occurs in a wide variety of patterns:
Directional
Stabilizing
Disruptive
Balancing
80
Directional Selection
changes the average value of a trait
81
- average values toward the other extreme
- reduces values toward the other extremes
- variation in the trait is reduced
Directional Selection
82
Stabilizing Selection
reduces genetic variation in a trait
83
- average value of a trait does no change over time
| - reduces both extremes in a population
Stabilizing Selection
84
Directional
more extreme
85
Directional
lower variation
86
Stabilizing
to average
| "Goldilocks"
87
Stabilizing
lower variation
88
Stabilizing
higher mortality at both extremes
89
Disruptive Selection
increases variation in a trait
90
- intermediate phenotypes are selected against
- extreme phenotypes are favored
- Overall amount of genetic variation in the population is maintained
Disruptive
91
Disruptive
anything but average
92
Disruptive
for extremes - means the same
93
Disruptive
higher variation
94
Balancing Selection
maintains variation in a trait
95
- occurs when no single allele has a distinct advantage
| - there is a balance among several alleles in terms of their fitness and frequency
Balancing Selection
96
balancing
selection against phenotype
97
balancing
mean stays the same
98
balancing
variation is maintained
99
neither allele good in homozygotes
balancing
100
heterozygote = most fit
balancing
101
fitness
survival and reproduction
102
sexual selection = natural selection
higher reproductive success at cost of survival
103
sexual di(two)morphism(shape)
fitness
104
eggs are "expensive"
fundamental asymmetry of sex
105
Genetic Drift
any change in allele frequencies in a population due to chance (sampling error)
106
Founder effect
genetic drift caused by a small number of individuals establishing a disjunct population.
107
immigrants establish a new population
founder effect
108
New population is likely to have different allele frequencies than the source population, by chance
founder effect
109
Genetic Bottleneck
genetic drift caused by a sudden, dramatic reduction in the number of individuals in a population.
110
High mortality strikes individuals at random
Genetic bottleneck
111
this population is likely to have different allele frequencies than original population, by chance
Genetic Bottleneck
112
The CNGB3 gene codes for a protein necessary for
color vision
113
The frequency of a recessive, loss-of-function allele is less than _____ in the general population
1.0%
114
Individuals homozygous for this allele have...
achromatopsia
115
Mutation
increases genetic variation and provieds the raw material for natural selectoin, but is generally deleterious
116
Non-random mating
| Migration
have mixed effects on populations
117
Genetic drift
cannot improve the fit of a population to its environment
118
Natural selection
frequently reduces variation, but is the only process by which organisms become better suited to their environments
119
Natural selection reduces variation
directional and stabilizing
120
Natural selection is strong if the payoff is big
- predators vs. prey
- male sea lions vs. female
- antibiotic resistance in bacteria
121
If natural selection is weak, variation is maintained or increases
- adaptive radiations
| - maintenance of non-coding and vestigial features
122
disruptive selection causes...
divergence
