t10 phylogeography
TRANSCRIPT
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Topic 10: Phylogeography
� What is phylogeography?
� How does it differ from biogeography
� What are the key concepts of
phylogeography?
� Some herpetological examples
What is phylogeography?
� An offshoot of biogeography
� Originated with advent of ______________________
� A bridge between ______________ genetics and __________________
� A bridge between _________________ and _________________
� Originally looking at population interrelationships using mitochondrial DNA
What is phylogeography?
� Has commonalities with biogeography
� Roles of vicariance and dispersal are important
� Interested in how ________ ____________ have shaped geographic distributions
� Focused on ___________ of divergences and events
� Ultimately goal is a ______________ approach
� Different taxa with similar distributions explained by similar phenomena
Avise 2000, Fig 1.1
What is phylogeography?
� Phylogeography also has differences from biogeography
� __________________ or very closely related species studied
� Focus on population level processes
� Not reproductively isolated –__________________
� Phylogeny can be ________
� Generally uses genetic data
� Focus on mtDNA
� Haplotype networks and population genetic theories
Koblmuller et al. 2007
What are the key concepts of phylogeography?
� _______________________� Phylogeny with taxa replaced by ______________
� Can consider shifts in distribution during evolution
� Because OTUs are intraspecific, the focus is localities
Pough et al. 2004, Fig 5-22 Wiens and Penkrot 2002
Population-level phylogeny of Sceloporus
jarrovii sub-taxa
� Intraspecific focus� Gene flow
� Lots of breeding between individuals within a population
� Some interbreeding between individuals among populations
� Major implications
� A reticulate phylogeny
� Populations are not _________________
� Phylogeny can be _________________
What are the key concepts of
phylogeography?
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� ______________________
� Don’t need to force data into a dichotomous structure
� ______________ – a unique haploid genotype at a locus
� Single nucleotide polymorphism
� A haplotype network can show:
� Haplotype _____________
� Haplotype _____________
� Haplotype _____________
� Haplotype _____________
Rabemananjara et al. 2007
What are the key concepts of phylogeography?
� Haplotype networks can be very complex!
� Numbers give number of nucleotide changes
� Colors correspond to _______________
� Keep in mind that this is intraspecific, so haplotypes tend to be quite similar
Rabemananjara et al. 2007
What are the key concepts
of phylogeography?
� Recent gene flow between species of Mantella cowani group
Rabemananjara et al. 2007
What are the key concepts
of phylogeography?
Pough et al. 2004, Fig. 5-14, 15
What are the key concepts of phylogeography?
� _____________________� Typical pattern for populations with gene flow between them
� Less and less gene flow as the populations are ______ ______________________ ______________________
� Example: Cerberus rynchops
� MtDNA sequence divergence increases with geographic separation
� Phylogeography operates on the cusp of speciation
� The formation of __________ ________________ is a focus
� Species concepts are important
� ______________ is not instant
� __________________ Concept of species reconciles other species concepts
� Species concept vs. species criterion
� Sequential attainment of species criteria
De Queiroz 1998
Reproductive isolation
Morphologically distinct
What are the key concepts
of phylogeography?
� Phylogeography of Thecadactylus
Kronauer et al. 2005; Bergmann and Russell 2007
• No morphological synapomorphies
• ~25% cyt b divergence
• Split into:• T. rapicauda
• T. solimoensis
What are the key concepts of phylogeography?
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� Stages of population differentiation and ultimately speciation from a population point of view
???
� When a geographic barrier divides a population:
� 2+ sub-populations
� ________________
� Multiple lineages in each
� So, what are they (A & B)??
What are the key concepts of phylogeography?
� Lineages become extinct through time
� Subpopulations eventually become monophyletic
� _________________________________________________
??Time
What are the key concepts of phylogeography?
1A 3A 3B2B1B 2A
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� Why mtDNA?� _______________________
� No recombination to give complex signal
� Can be biased by sexual differences (e.g. in dispersal)
� Can be biased by hybridization
� _______________________� Fast evolution� Appropriate for population-
level analyses
� _______ effective population size – faster to fixation
� Easy to amplify & sequence
De Queiroz 1998
What are the key concepts of phylogeography? Herp Phylogeography
� Eumeces fasciatus
� Longitudinal structuring of
haplotypes
� Consistent with hypothesis
of __________________
� During Pleistocene, North America experienced some glacial maxima
� Organismal distributions retreated south
� Sometimes, near the glacial maximum, little pockets of habitat
remained = refugia
Howes et al. 2006
Herp Phylogeography
� Eumeces fasciatus
� Haplotypes that radiated from these refugia are highly distinct
� Oklahoma and Wisconsin
� Deep divergences predate the Pleistocene
� Carolinas
� Lots of ___________ east of the Mississippi River
� River is a barrier to gene flow
� Poor genetic differentiation
Howes et al. 2006
Herp Phylogeography
� Ensatina eschscholtzi
(Plethodontidae)
� West coast USA, “______
__________” around
central valley, California
� Gene flow between neighboring subspecies
� How are they related?
� Where did they originate
from?
� How have they dispersed?
Vences and Wake 2007
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Herp Phylogeography
� Ensatina eschscholtzi (Plethodontidae)
Vences and Wake 2007
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Herp Phylogeography
� Ensatina eschscholtzi(Plethodontidae)
� Patterns of genetic similarity
� Suggest _________
________________
� Circles indicate:
� Areas of secondary ____________
� ____________
Vences and Wake 2007
Herp Phylogeography
� Comparative phylogeography
� Do we see concordant
patterns in multiple species?
� If yes:
� Strengthens hypotheses of common ______________ _________________
� That similar historical events shaped how many _____________________
� If no:
� Maybe factors unique to our species of interest
Vences and Wake 2007
Herp Phylogeography
� Comparative phylogeography
Feldman & Spicer 2006
Charina bottae Lampropeltis zonataElgaria multicarinata
Herp Phylogeography
Leache et al. 2009; Photo © J Melli
� Phylogeography of the Phrynosoma coronatum complex
� One species, or as many as five!
� Much debated over the years
� Look at both morphological and DNA data
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Herp Phylogeography
Leache et al. 2009
� Each of the 5 hypothesized species forms a ____________
� Only one (red) is distinct from all the others with __________
Herp Phylogeography
Leache et al. 2009
� One (red) or two (orange) are distinct in head shape
� Two (red & orange) are distinct climatically
Herp Phylogeography
Leache et al. 2009
� Three valid species?
� P. blainvillii (blue, green, yellow)
� P. cerroense (orange)
� P. coronatum (red)
� But, what is wrong with doing this?
� ___________________________ ___________________________
___________________________