Quartet Partitioning Reveals Hybrid Origins of the Vertebrate

  • Michael Syvanen
  • Bryan Ericksen
  • Simone Linz
  • Jonathan Ducore


It is generally accepted that humans and sea urchins are deuterostomes and that fruit flies and jelly fish are outgroups. However, when we analyzed proteins from the genomes of these four species and submitted them to 4 taxa phylogenetic analysis, we found that, while as expected, most of the proteins (563) supported the notion of human and sea urchin in one clade and jelly fish and fruit flies in the other clade (Tree1), a large number of proteins (353) showed human and fruit fly in one clade with the sea urchin and jelly fish in the other (Tree3). Homologs were found in the genomes from 5 other metazoa. Tree1 proteins resulted in the expected 9 taxa tree, while the Tree3 proteins show vertebrates, to the exclusion of the other chordates, in the protostome clade. The two 9 taxa trees were fused into a single most parsimonious net that supports an introgression event between a vertebrate ancestor and a primitive protostome.


Horizontal Gene Transfer Phylogenetic Network Horizontal Gene Transfer Event Tree3 Partition Cambrian Explosion 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer International Publishing Switzerland 2014

Authors and Affiliations

  • Michael Syvanen
    • 1
  • Bryan Ericksen
    • 1
  • Simone Linz
    • 2
  • Jonathan Ducore
    • 3
  1. 1.Department of MicrobiologyUniversity of California at Davis School of MedicineDavisUSA
  2. 2.Department of Computer Science, Center for Bioinformatics (ZBIT)University of TübingenTübingenGermany
  3. 3.Department of PediatricsUniversity of California at Davis School of MedicineDavisUSA

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