Download Evolution

Zoogeografia
Dr. Valerio Ketmaier
[email protected]
Variation
The synthetic theory of evolution
Nothing in Biology Makes Sense Except in the Light of Evolution
Dobzhansky T (1973) The American Biology Teacher 35:125-129
Evolution
evolvere [lat.]: develop based on something already existing
Biological (or organic) evolution is change in the properties
of populations of organisms or groups of such populations,
over the course of generations.
Futuyma, 1998
Evolution can be precisely defined as any change in the
frequency of alleles within a gene pool from one generation
to the next.
Curtis & Barnes, 1989
Preconditions for evolution
• Inherited similarity
•  Variation
•  Selection
Evolution of Influenza A
virus in New York State
413 complete genomes, ML
Changing environment =>
•  inherited similarity
•  (unpredictable) variation
•  selection
New York:
1997–1998, orange;
1998–1999, yellow;
1999–2000, light green;
2001–2002, dark green;
2002–2003, light blue;
2003–2004, dark blue;
2004–2005, purple;
global background, red.
Nelson et al. 2006, PLOS Pathogens
Principles of evolution
Evolution is a historical process => inheritance
No design in variation => mutations unpredictable
Selection occurs by differential survival/reproduction
of different genotypes
Selection leads to adaptation
Evolution as a historical process
Constraints by previous adaptations
Barton et al. 2007
No design in variation
Escherichia coli under stressful
freezing, thawing & growth
(FTG)
Insertions/deletions in cardiolipin synth.
=> cls down, phosphatidilglycerol up
=> increased membrane fluidity
No predictable course
of adaptation
Insertions near universal stress proteins
=> uspB down, uspA unaffected
=> uspB possibly related to membrane fluidity
Sleight et al. 2008, Genetics
Selection occurs by differential survival/
reproduction of different genotypes
Experimental evolution of learning ability in Drosophila
Circles: even numbered generations
Squares: odd numbered generations
Triangles: control populations
Higher learning ability causes
higher reproduction („fitness“)
Mery & Kawecki T. J. 2002, PNAS
Selection leads to adaptation
Local adaptation in
Poecilia mexicana
Morphometrics, 13 landmarks
blue: non-sulfidic surface
yellow: sulfidic surface
Plasticity or
orange (LA): non-sulfidic cave
red (CA): sulfidic cave
Inherited change
Genetics, 10 microsatellites
? Tobler et al. 2008, Evolution
Plasticity or inherited changes ?
Phenotypic plasticity => morphological differences caused by the
environment (heritability = 0)
Differences purely genetic => morphological differences
genetically determined (heritability = 1)
Heritability: h2 = VGenotype/VPhenotype
Phenotypic trait with H2=0 (rare)
„Acquired“ lack of tail in mice
August Weismann (1892):
(from Kutschera 2006)
Phenotypic trait with H2=1 (rare)
Mendel experiments
Traits based on a single
gene or tightly linked genes,
no environmental influence
Common:
•  Traits based on multiple
gene loci (QTLs)
•  Environment impacts
traits
What is synthesized in the
synthetic theory of evolution?
Evolutionary theory
„meets“
Genetics
Mendel 1822-1884
Darwin
1809-1882
De Vries
1848-1935
Haeckel 1834-1919
Morgan 1866-1945
Evolutionary theory
Principles:
• Phenotypic variation
• Limited resources
• Survival of the fittest
(natural selection)
Side notes:
• No genetics
• Focused on quantitative
traits
Mendelians
Principles:
•  new species through single mutations
•  quantitative variation not heritable
•  only discrete variation relevant
•  natural selection is old-fashioned
•  mutations and selection are mutually exclusive
Side note:
•  focused on single gene traits
•  quantitative genetics unknown
Synthetic theory of evolution (origin 1930-1950)
„Mutations create the variation, which selection acts upon“
Theodosius Dobzhansky
(Russian geneticist; 1900-1975):
•  1927 emigrated to USA
• „Genetics and the origin of species“ (1937)
•  biological species concept
Sir Julian Huxley
(English biologist; 1887-1975):
•  „Evolution, the modern synthesis“
(1942)
How did giraffes get a long neck?
Okapi
Creationism / Intelligent Design (ID):
•  Neck has been designed as an
adaptation
Giraffe
How did giraffes get a long neck?
Organic progression / Lamarckism
Continuous stretching
of neck
Inheritance of acquired
traits
How did giraffes get a long neck?
Synthetic theory of evolution
„Mutations create the variation, which selection acts upon“
•  Neck length is a phenotypically variable
quantitative trait
•  Part of the variation in neck length is based on
genetic variation
•  Individuals with longer necks have a higher
fitness
•  This selection on phenotypes increases frequency
Of QTL_alleles positively correlated with neck length
Preconditions for evolution
• Inherited similarity
•  Variation
•  Selection
Genetic variation
Mutations
•  point mutations
•  chromosome mutations
•  polyploidization
Recombination
•  sexual recombination
•  other types of recombination
Horizontal gene transfer
•  in prokaryotes
•  in eukaryotes
Mutation rates in various organisms
Rates in bacteriophages & prokaryotic microbes
(Drake 1999, Annals of the New York Academy of Sciences)
Mutation rates in various organisms
Mutation rates in higher eukaryotes
per base: highest for bacteriophages, lowest for higher eukaryotes
per genome: similar in all microbes, higher in higher eukaryotes
(Drake 1999, Annals of the New York Academy of Sciences)
Evolution of mutation rates in prokaryotes
Mutator alleles as fast track to adaptive evolution
(Taddeei et al. 1997, Nature)
Evolution of mutation rates in prokaryotes
Mutation rates in Pseudomonas with/without phages
Mutation rates with (black)/without (white)
phages (line is ancestral mutation rate)
(Pal et al. 2007, Nature)
67% phages extinct with mutator
33% phages extinct without mutator
Mutations are caused by ionizing radiation
Mutation rates in offsprings of Chernobyl accident liquidators
Random Amplified Polymorphic DNA (RAPD)
n
New
bands
New
bands (%)
CB
(internal
control)
18
5
0.019
CA
18
28
0.104
External
Control
28
1
0.002
1: mother
2: father (working as liquidator)
3: offspring conceived after exposure (CA)
4: offspring conceived before exposure (CB)
5: negative control
6: size standard
(Weinberg et al. 2001, Proc. R. Soc. B)
Mutations are caused by ionizing radiation
Impacts of the Fukushima nuclear accident on the pale grass
blue butterfly
F1-May 2011
(Hiyami et al. 2012, Nature)
Mutations are caused by ionizing radiation
Impacts of the Fukushima nuclear accident on the pale grass
blue butterfly
Sept 2011
(Hiyami et al. 2012, Nature)
Mutations are caused by ionizing radiation
Impacts of the Fukushima nuclear accident on the pale grass
blue butterfly
F2
(Hiyami et al. 2012, Nature)
Polyploidization
Chromosome number
in sturgeons
•  several polyploidizations
•  evolution towards
functional diploidy
Phylogeny based on cytochrome b
black: polyploidizations
(Ludwig et al. 2001, Genetics)
Hybridisation & recombination after secondary contact
Atlantic sea sturgeon
(spawns at 13-18°C)
European sturgeon
(spawns at >20°C)
Distribution of mitochondrial haplotypes
(part of Fig. 1; Ludwig et al. 2002, Nature)
Atlantic sturgeon: American females successful
in Europe
Baltic Sea
Canada
Gironde
MtDNA
(data from Ludwig
et al. 2002)
n=81
n=10
n=67
n=15
n=17
MHC
n=27
American (red), European (blue) and other (white) genotypes in sturgeons
(Tiedemann et al. 2006, Naturwissenschaften)
Hybridisation & recombination after secondary contact
Origin
2n
"oxy"
"stur"
I1-I4
HE
HO
American sea sturgeon (A. oxyrinchus)
St.Lawrence/ St. Johns (Canada)
54
52
1
1
0.07
0.04
European sturgeon (A. sturio)
Gironde (France)
34
-
33
1
0.06
0.06
Baltic sturgeon (A. oxyrinchus x sturio)
Baltic Sea (18th to 20th century)
30
6
10
14
0.79
0.73
(Tiedemann et al. 2006, Naturwissenschaften)
Amazon mollies (Poecilia)
P. latipinna-female
Gulf of Mexico
P. latipinna-male
Gynogenesis
Gynogenesis
MM
P. formosa-female (all-female species)
P. mexicana
Sexual
reproduction
M
P
P
MM
MP
(Schlupp et al., 1994, Science)
Lack of recombination in P. formosa
Characteristics in P. formosa
P. latipinna
P. mexicana
A
Allele size;
inferred
origin
HE
HO
n
A
Allele
size
HE
HO
n
A
Allele
size
HE
HO
(GT) 10
2
339,341* (l)
0.52
0.00
7
4
335-4
77
0.66
0.29
7
5
349-3
85
0.59
0.43
(GT)4CT(GT)6
1
199 (m)
0.00
0.00
7
9
207-2
63
0.92
0.86
7
1
199
0.00
0.00
(GA) 14
4
407*,411*,
413 (l)
393 (m)
0.67
1.00
7
5
403-4
17
0.76
0.57
7
1
393
0.00
0.00
(GA)16AA(GA)2
CA(GA)5
3
197 (l)
203,205* (m)
0.63
1.00
7
6
173-1
99
0.86
1.00
4
7
187-2
07
0.96
0.75
(AG) 12
2
146 (l)
154 (m)
0.52
1.00
7
1
146
0.00
0.00
7
3
148-1
54
0.58
0.29
(GA)13
2
118 (l)
126 (m)
0.52
1.00
7
3
118-12
2
0.54
0.71
7
5
126-1
36
0.79
0.71
(GA)22
3
122 (l)
144*,148 (m)
0.63
1.00
7
4
116-14
6
0.70
0.71
7
7
120-1
60
0.86
0.29
(TG)10
3
176,178 (l)
180 (m)
0.63
1.00
7
2
176,
178
0.49
0.43
7
4
174-1
82
0.63
0.29
Repeat
sequence
(Tiedemann et al. 2005, Molecular Ecology Notes)
Bdelloidea
(Rotifers)
Only females known
Unisexual reproduction:
•  no genetic exchange among lineages
•  genetic depletion
•  +/- identical offspring
Alternation of generations in rotifers
•  amictic females
=> Parthenogenesis
•  mictic females
•  unfertilized eggs
=> males
•  fertilized eggs => dormant eggs
=> amictic females
Horizontal gene transfer
in viruses
Barton et al. 2007
Horizontal gene transfer and the origin of eukaryotes
Last Universal Common Ancestor (LUCA)