Specialized impulse conduction pathway in the alligator heart

Bjarke Jensen, Bastiaan J. Boukens, Dane A. Crossley, Justin Conner, Rajiv A. Mohan, Karel van Duijvenboden, Alex V. Postma, Christopher R. Gloschat, Ruth M. Elsey, David Sedmera, Igor R. Efimov, Vincent M. Christoffels

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


Mammals and birds have a specialized cardiac atrioventricular conduction system enabling rapid activation of both ventricles. This system may have evolved together with high heart rates to support their endothermic state (warm-bloodedness) and is seemingly lacking in ectothermic vertebrates from which first mammals then birds independently evolved. Here, we studied the conduction system in crocodiles (Alligator mississippiensis), the only ectothermic vertebrates with a full ventricular septum. We identified homologues of mammalian conduction system markers (Tbx3-Tbx5, Scn5a, Gja5, Nppa-Nppb) and show the presence of a functional atrioventricular bundle. The ventricular Purkinje network, however, was absent and slow ventricular conduction relied on trabecular myocardium, as it does in other ectothermic vertebrates. We propose the evolution of the atrioventricular bundle followed full ventricular septum formation prior to the development of high heart rates and endothermy. In contrast, the evolution of the ventricular Purkinje network is strongly associated with high heart rates and endothermy.

Original languageEnglish (US)
Article numbere32120
StatePublished - Mar 22 2018


  • American alligator
  • Tbx3
  • Ventricular septum
  • conduction system
  • developmental biology
  • evolution
  • evolutionary biology
  • genomics
  • stem cells

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)
  • Neuroscience(all)


Dive into the research topics of 'Specialized impulse conduction pathway in the alligator heart'. Together they form a unique fingerprint.

Cite this