Why mammals have poor regenerative ability has remained a long-standing question in biology. In regenerating vertebrates, injury can induce a process known as epimorphic regeneration to replace damaged structures. Using a 4-mm ear punch assay across multiple mammalian species, here we show that several Acomys spp. (spiny mice) and Oryctolagus cuniculus completely regenerate tissue, whereas other rodents including MRL/MpJ ‘healer’ mice heal similar injuries by scarring. We demonstrate ear-hole closure is independent of ear size, and closure rate can be modelled with a cubic function. Cellular and genetic analyses reveal that injury induces blastema formation in Acomys cahirinus. Despite cell cycle re-entry in Mus musculus and A. cahirinus, efficient cell cycle progression and proliferation only occurs in spiny mice. Together, our data unite blastema-mediated regeneration in spiny mice with regeneration in other vertebrates such as salamanders, newts and zebrafish, where all healthy adults regenerate in response to injury.
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Funding for this work was provided by the National Science Foundation (NSF) and the Office for International Science and Engineering (OISE) to A.W.S. (IOS-1353713) and V.O.E. (IOS-1353857). Additional funding was provided to A.W.S. by the University of Kentucky.
Sequencing data have been deposited in the NCBI database under accession code GSE71761.
Gawriluk, Thomas R.; Simkin, Jennifer; Thompson, Katherine L.; Biswas, Shishir K.; Clare-Salzler, Zak; Kimani, John M.; Kiama, Stephen G.; Smith, Jeramiah James; Ezenwa, Vanessa O.; and Seifert, Ashley W., "Comparative Analysis of Ear-Hole Closure Identifies Epimorphic Regeneration as a Discrete Trait in Mammals" (2016). Biology Faculty Publications. 108.