jokearoo

Harder, Better, Faster, Stronger: "
Host-Parasite Coevolution
"
Kaylee Byers and Matthew Osmond"
Smithsonianscience.org"
Smithsonianscience.org"
imol.vub.ac.be"
Single species?"
Single vs. Multiple Species"
Devianart.com"
Interspecific Interactions"
Predator-Prey"
Banffcentre.ca"
youtube.com"
math.duke.edu"
Competition"
jokeroo.com"
king.portlandschools.org"
nature.com"
Host-Parasite"
globalbiodefense.com"
wordpress.com"
lymedisease.org.au"
Intraspecific Interactions"
vetmedillinois.edu"
pbs.orr"
openi.nlm.nih.gov"
Host-Parasite Interactions"
Parasite"
–  Derives benefit from the host"
Intestinal"
Blood-Borne"
Ectoparasitic"
Photos: sciencephoto.com, nakedscientist.com"
Host-Parasite Interactions"
Host"
–  Harbors another organism on/in itself"
amazinglist.net"
theinformationarchives.com"
en.wikipedia.org"
Flickr.com"
usi.edu"
How can a trait in one
population influence the
evolution of a trait in another
population?"
Matching-Alleles Model"
Interaction of genes in host and
parasite"
"
"
"
"
"
"
Flor. 1956. Adv. Genet. 8:29-54"
bergulson.uchicago.edu"
H.H. Flor"
agric.gov.ab.ca"
Parasite “chases” host, host “evades” parasite"
"
Here we follow Otto and Day (2007)"
Some Assumptions"
Haploid"
Two alleles"
Infinite, well-mixed populations"
Costs to host and parasite are constant"
en.wikipedia.org"
Parameters"
Parasites with surface molecule gene with two
alleles:"
"
"a"
A"
"
Host with a receptor gene with two alleles:"
"
"
B"
b"
"
Successful Attacks"
Parasite with allele “A” à Host with allele “B” Parasite with allele “a” à Host with allele “b” B"
A"
Parasite wins! globalbiodefense.com"
Unsuccessful Attacks"
Parasite with allele “A” à Host with allele “b” Parasite with allele “a” à Host with allele “B” A"
Host wins! b"
parasitesandvectors.com"
eyeofscience.net"
Costs"
Successful a9acks cost the HOST Sh Unsuccessful a9acks cost the PARASITE Sp Relative Benefit Matrix"
Host
Genotype!
Parasite Genotype!
A"
a"
"
B"
Infection"
Parasite: 1"
Host: 1-Sh"
No Infection"
Parasite: 1-Sp"
Host: 1"
"
b"
No Infection"
Parasite: 1-Sp"
Host: 1"
Infection"
Parasite: 1"
Host: 1-Sh"
Otto and Day. 2007. A Biologistʼs Guide to Mathematical Modeling in Ecology and Evolution "
How do the frequencies of
the “A” and “B” allele change
with time?"
Equilibria"
Allele frequency in parasite !p"
1.0
0.8
0.6
0.4
0.2
0.0
0.0
Allele frequency in host !q"
0.2
0.4
0.6
0.8
1.0
Equilibria"
Allele frequency in parasite !p"
1.0
0.8
Unstable"
0.6
0.4
0.2
0.0
0.0
Allele frequency in host !q"
0.2
0.4
0.6
0.8
1.0
Equilibria"
Allele frequency in parasite !p"
1.0
0.8
Stable"
0.6
0.4
0.2
0.0
0.0
Allele frequency in host !q"
0.2
0.4
0.6
0.8
1.0
Stability"
Stable?"
(p)!
(p)!
Unstable"
(q)!
(q)!
(p)!
Cycles"
(q)!
Parasite"
medicalmicro.org"
Host"
equinedesktop.com"
Cycles"
Parasite"
Host"
Parasite"
Host"
The Red Queen Hypothesis"
bluesci.org"
amazon.ca"
Examples"
Daphnia
(host)
Bacteria"
(parasite)"
en.wikipedia.org"
Personal.umich.edu"
Decaestecker et al. 2007. Nature, 450: 870-873"
Examples"
Snail
(host)
Trematode"
(parasite)"
en.wikipedia.org"
Personal.umich.edu"
Dybdahl & Lively. 1998. Evolution, 52: 1057-1066"
Conclusions"
Species interactions
influence evolution"
"
Simple interactions can
create complex dynamics"
"
In nature, certainly more
complicated"
–  More than two species"
–  More than one locus"