Fields connected to Phylogeography Microevolutionary disciplines Ethology Demography Population genetics

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1 Stephen A. Roussos Fields connected to Phylogeography Microevolutionary disciplines Ethology Demography Population genetics Macrevolutionary disciplines Historical geography Paleontology Phylogenetic biology Spanning the fields of microevolutionary disciplines and macroevolutionary disciplines is the field of molecular genetics. It is the one field that can possess disciplines at both of these levels and is the reason why 70% of all phylogeographic studies are based primarily or exclusively on mitochondrial DNA. Avise (2000) 1

2 Molecular Genetics Mitochondrial DNA (mtdna) Can be used as a evolutionary clock Very accurate, feasible and effective with modern technology Maternally inherited Paleaogeography Barriers of Historical Dispersal Oceanic, lakes, rivers, canals Mountain ranges, insular formation Major Climatic changes Glaciations Volcanic activity Tectonic movement 2

3 Pleistocene Glaciation at maximal extent 20,000 years ago Hewitt (2000) Pleistocene glaciation 18,000 20,000 years ago was the last glacial maximum which h altered the landscape and climate across the globe. Exposed Beringian land bridge. Connected North America with Russia. Exposed the Sundra shelf. A land bridge connecting Indonesia with Southeastern Asia Connected islands of the UK, Japan, and other insular areas worldwide Hewitt (2000) 3

4 Refugial sites The last glaciation created faunal and floral refugial sites throughout the globe In North America; The southeastern, southwestern and central American refugial sites (Waltari et al. 2007) In Europe; The Balkan Peninsula, the Apennine Peninsula and the Iberian Peninsula (Taberlet et al. 1998) In Asia most refugial spots were located in the Indian Peninsula and Southeastern peninsula Ecological Niche Models (ENMs) Technique establishes spatial distribution of suitable conditions for species Helps locate possible distributional ranges at current time Helps locate possible distributional ranges of historical times Glacial refugia Divergence routes May not agree with phylogenetic studies using molecular genetics Waltari et al. (2007) 4

5 ENMs vs. Molecular Phylogenetics ENMs may not agree with phylogenetic interpretations of historical distributions and refugia. Wiltari et al. (2007) Baja Peninsula refugial site for the California Gnatcatcher (Polioptia californica) Waltari et al. (2007) 5

6 Central and Southwestern refugial site for the Western Diamondback Rattlesnake (Crotalus atrox) Waltari et al. (2007) Central and Eastern refugial sites for the Black Ratsnake (Elaphe obsoleta) Waltari et al. (2007) 6

7 Last Glaciation Maximum in Europe There have been three refugial sites found to have existed during the last glacial period in Europe. The Balkan Peninsula The Apennine Peninsula The Iberian Peninsula Dispersal of European fauna after the Pleistocene glaciation using DNA differences Hewitt (2000) 7

8 Volcanic eruptions: Mt. Krakatoa Recolonization of fauna in an event of a volcanic eruption has been monitored in several groups of animals within the last century. Bats Stomatopods Butterflies Termites Land birds Plants STATISTICAL PHYLOGEOGRAPHY Knowles and Maddison 2002 Objective approach vs. ad hoc approach Since the field of phylogeography has been growing, great caution needs to be made about conclusions on past events based solely on genetic variation. Using data outside of molecular sources (i.e. paleontology, palaeogeography ) that may offer to the history that underlies the structure suggested by molecular genetic analysis. Combining the disciplines of statistics and phylogeography will offer a more accurate stochastically derived expectation of historical events rather than explicitly considering historic geographic scenarios, which has been a trend in many phylogeographic studies. 8

9 Gene Divergence vs. Population Divergence Knowles and Maddison (2002) Nested Clade Phylogenetic Analysis (NCPA) Holsinger (2008) This form of analysis has become a widely used technique in phylogeographical studies It uses parsimony to construct a statistically supportable haplotype network Once nested clades are identified using molecular genetics then; Test for association iti between geography and haplotype distribution Identify the processes that could have produced the association 9

10 Geographical Information Systems (GIS) GIS has been used in phylogeographical studies to create sophisticated maps that can be used in many scenarios depending on the specific study. GIS incorporates maps of all types (i.e. topographical maps, climatic maps, political maps, energy consumption, etc.) By incorporating the data that influences the taxa of your study, you are able to analyze those relations to a possible range on a map. Ormsby et al. (2004) 10