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Wattles and Wombats: Molecular rate variation and Biodiversity Xavier Goldie The University of Auckland The Australian National University. Outline:. Biodiversity and Evolution Evolutionary Speed in Australian Plants Evolutionary Speed Hypothesis Productivity and the Water-Energy Balance

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Outline:

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  1. Wattles and Wombats:Molecular rate variation and BiodiversityXavier GoldieThe University of AucklandThe Australian National University

  2. Outline: • Biodiversity and Evolution • Evolutionary Speed in Australian Plants • Evolutionary Speed Hypothesis • Productivity and the Water-Energy Balance • Outcomes • Molecular rates in Mammals • Diversification and molecular rates: crash course • Outcomes

  3. Biodiversity and Evolution • What drives diversification? • SPECIATION - EXTINCTION • Why are species unevenly distributed - • Spatially? • Phylogenetically? • Temporally?

  4. Chiroptera Carnivora + Shrews and stuff Xenarthra Afrotheria Cetartiodactyla + Metatheria Primates + Lagomorphs Rodents

  5. Evolutionary Speed in Australian Plants Climate and Biodiversity

  6. Rohde’s Evolutionary Speed Hypothesis (ESH) Bromham and Cardillo 2003

  7. Rohde’s ESH deals specifically with the relationship between global temperature and biodiversity However… Terrestrial biodiversity is linked most tightly to the interaction of temperature and the physical state of water “Water-Energy Balance” (Hawkins et al 2003) “Productivity” (Gillman and Wright, 2006)

  8. Is Rohde’s ESH applicable to gradients of water availability?

  9. Species Richness Rainfall Productivity

  10. “Dry” Amyema maidenii Amyema congener “Wet”

  11. Branch length Trait • Branch length Trait P.A. • Branch length Trait  30 Phylogenetically Independent contrasts

  12. Significantly more (23 of 30) comparisons resulted in longer “Wet” branch lengths (Sign Test: P = 0.005) The rate of nucleotide substitution in “Wet” zone taxa was on average more than twice that of closely related “Dry” zone congeners (Wilcoxon Signed Rank Test: W = 93, P = 0.003). Goldie et al., 2010

  13. Results are consistent with the evolutionary speed hypothesis Optimised water-energy balance may act to increase micro-evolutionary rates in mesic areas Arid conditions may lead to slower tempo of micro-evolution

  14. Rohde’s Evolutionary Speed Hypothesis Bromham and Cardillo 2003

  15. Molecular Rates Wright et al 2006 Lanfear et al In Prep Webster et al 2003 Pagel et al 2006 Speciation Rates

  16. Molecular Rates in Mammals

  17. What is the relationship between the rate of molecular evolution, and diversification, in mammals?

  18. Whole Mitochondrial Genomes and Nuclear Genes Estimated Synonymous, Non-Synonymous and total substitution rates (MG94_REV_3x4 in HyPHY) Mitochondrial Sister-clades at roughly ordinal, familial and generic level Nuclear Sister-Clades in Mammalia, Eutheria, Metatheria, Euarchontoglires and Laurasiatheria Sign-Tests and Parametric Regression Included Body Size in Multiple Regression

  19. No consistent relationship between molecular rates and clade size - mitochondrial or nuclear Body Size Effect detected in nuclear genes, but not in mitochondrial Saturated Synonymous Rates in mitochondrial genes “RY” Coded four-fold degenerate sites - record only synonymous Transversions (T or C ↔ G or A) No relationship (Goldie et al, In Prep)

  20. Eutheria ML Brlen versus Clade Size P = 0.00545 But not repeated in dN or dS

  21. Welch et al 2007 Mitochondrial dS P = 0.1260

  22. BUT WHAT DOES IT ALL MEAN?

  23. Lack of apparent relationship between mammalian molecular rates and diversification rates? Molecular rates are not central to the diversification process in mammals Different process operating between plants and mammals - has been suggested But why birds, and not mammals?

  24. Gillman et al 2009 Higher rates of molecular evolution in tropical mammals versus temperate PICs Interpreted as support for Evolutionary Speed Hypothesis driving Latitudinal Species Gradients Bassariscus astustus Bassariscus sumichrasti

  25. Rohde’s ESH Bromham and Cardillo, 2003

  26. Acknowledgements: Shane Wright Len Gillman Lindell Bromham Rob Lanfear Nga Pae O Te Maramatanga Maori Centre of Research Excellence The Australian National University

  27. Questions?

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