Meeting Abstract

S5.6  Tuesday, Jan. 5  Evolutionary loss of animal regeneration: pattern and process BELY, A.E.; Univ. of Maryland, College Park abely@umd.edu

Regeneration ability has been greatly restricted or altogether lost numerous times among animals. Yet despite its prevalence, regeneration loss and the mechanisms by which it occurs remain poorly studied. I will provide a phylogenetic overview of regeneration ability across animals, highlighting both old and recent regeneration losses, and will discuss diverse hypotheses that have been proposed to explain why and how regeneration loss occurs. I will also describe our findings from studies on a group of small asexual annelids, the naidines, in which the ability to regenerate a head has been lost multiple times. In one species that has recently lost head regeneration abilities, amputation within the fission zone, a narrow proliferative region that forms during asexual reproduction, can still elicit regeneration of an essentially normal head. This finding demonstrates that regeneration abilities can remain latent and still be elicited following a recent evolutionary loss of regeneration.