On patterns of coevolution across cophylogenies

Transcription

1 On patterns of coevolution across cophylogenies Mark Merilo, Sarah J. Adamowicz, R. Ayesha Ali Evolution 03 Snowbird, Utah Monday, June 4 th, 03

2 Species interactions wormwould, (00), Parasitic Wasp [ONLINE]. Available at: [Accessed 0 January 3] Fir000/Flagstaffotos, (007), Leaf Hopper nymph of the Common Jassid (Eurymela fenestrata) [ONLINE]. Available at: [Accessed 0 January 3]. Dr Graham Beards, (009), Electron micrograph of Bacteriophages [ONLINE]. Available at: [Accessed 0 January 3]. John Severns, (006), Honey bee [ONLINE]. Available at: [Accessed 0 January 3]. Richard Naylor, (009), Parasitoid wasps [ONLINE]. Available at: [Accessed 0 January 3].

3 Symbiotic relationships Persistent, recurring biological interactions Mutualism, commensalism, parasitism Obligate and facultative relationships Shared phylogenetic topology Reciprocal speciation between the two associated lineages; cospeciation But what about when they don t match? Phylogenetic reconstruction Superimpose phylogenies, explain differences with events Jan Derk, (00), Common Clownfish [ONLINE]. Available at: [Accessed 0 January 3]. Rafael Barbizan Sühs, (006), Wasp [ONLINE]. Available at: [Accessed 0 January 3]. Brian Valentine, (006), Small wasp parasitising aphids [ONLINE]. Available at: [Accessed 0 January 3]. 3

4 Coevolutionary Events Event types Cospeciation Sorting Cospeciation Sorting Duplication Host switch Duplication Host switch Host Symbiont 4

5 Past research Specific, small scale studies Mostly single cophylogeny comparison Tested individually for congruence No direct comparisons between phylogenies 5

6 Questions Is the symbiont phylogeny dependent on the host phylogeny? How can the coevolutionary history of symbiotic species be quantified & compared across groups? How do profiles of coevolutionary events differ across cophylogeny classifications? Latitude, transmission (horizontal, vertical), association (ecto, endo, intracellular), etc. 6

7 Overview of analysis Co-phylogeny collection Single, standardized Web of Science search Both symbiont phylogenies, and associations Transfer of cophylogenies to digital format Co-phylogenetic history reconstruction Core-PA (cost-based: fixed, parameter adaptive) Develop permutation test Use dirmult package in R 7

8 Symbiont categories Josh Grosse, (00), Roundworm [ONLINE]. Available at: [Accessed 0 January 3]. CDC/Vector Ecology & Control Laboratory, (007), Flea [ONLINE]. Available at: [Accessed 0 January 3]. Thomas Splettstoesser, (0), Cowpea mosaic virus [ONLINE]. Available at: [Accessed 0 January 3]. 8 Rafael Barbizan Sühs, (006), Wasp [ONLINE]. Available at: [Accessed 0 January 3].

9 Overview of analysis Co-phylogeny collection Single, standardized Web of Science search Both symbiont phylogenies, and associations Transfer of cophylogenies to digital format Co-phylogenetic history reconstruction Core-PA (cost-based: fixed, parameter adaptive) Develop permutation test Use dirmult package in R 9

10 Dirichlet distribution How to compare cophylogeny event profiles? Given total number of coevolutionary events, event counts follow a multinomial distribution Extension of binomial distribution for binary data Assume event proportions among host-symbiont pairs within a group (e.g. latitude zone) are similar Expect variance within these groups A Dirichlet distribution provides a model for how these proportions vary 0

11 Dirichlet model & permutation test Fit Dirichlet distribution model to event counts Log Likelihood Ratio Test (LLRT) statistic Randomized permutations to build distribution Tropical Temperate Tropical Temperate Cospeciation Sorting 8 X 999 Cospeciation Sorting Duplication 4 Duplication Host-switch Host-switch Calculate LLRT statistic Calculate LLRT LLRT statistic

12 LLRT statistic

13 Exploratory biological results (α = 0.) Of interest for further study Ecto-endo symbionts (expected) Innate-adaptive immune system (vert/invert) Tropical vs. temperate Not significant Horizontal/vertical transmission (unexpected!) Parasites/mutualist symbionts Presence/absence of secondary hosts Tropical-subtropical 3

14 Parameter Adaptive results: Ratios of Proportions Speciation Event Comparison Cospeciation Sorting Duplication Host-switch p Tropical vs Temperate Ecto- vs Endosymbiont Adaptive vs Innate * * Vertebrate vs Invertebrate immune system Less host-switching in the tropics 4

15 Parameter Adaptive results: Ratios of Proportions Speciation Event Comparison Cospeciation Sorting Duplication Host-switch p Tropical vs Temperate Ecto- vs Endosymbiont Adaptive vs Innate * * Vertebrate vs Invertebrate immune system Less host-switching in the tropics 5

16 Parameter Adaptive results: Ratios of Proportions Speciation Event Comparison Cospeciation Sorting Duplication Host-switch p Tropical vs Temperate Ecto- vs Endosymbiont Adaptive vs Innate * * Vertebrate vs Invertebrate immune system More host switching in ecto-symbionts 6

17 Parameter Adaptive results: Ratios of Proportions Speciation Event Comparison Cospeciation Sorting Duplication Host-switch p Tropical vs Temperate Ecto- vs Endosymbiont Adaptive vs Innate * * Vertebrate vs Invertebrate immune system More cospeciation and host-switching in hosts with adaptive immune systems 7

18 Conclusions & future directions Conducted meta-analysis of cophylogenies Developed statistical test to compare event profiles from several copylogenies Identified knowledge gaps requiring study Repeat comparisons within specific taxa Perform Dirichlet regression test to simultaneously include several factors into one parsimonious model 8

19 Acknowledgements Jinzhong Fu, Alex Smith Nicolas Wieseke Adamowicz, Hebert labs 9