Meeting Abstract

P2.84  Thursday, Jan. 5  Experimental whole body regeneration among botryllid ascidian species in San Francisco Bay CHOW, B.*; WRAY, M.; VILLINES, B.; PINNICK, G.; SHEETS, E.; SPAULDING, J.; COHEN, C.S.; RTC, San Francisco State University; CSU, SLO; RTC, San Francisco State University

Regeneration processes show a broad phyletic distribution and dramatic variation in potential across diverse organisms. Colonial ascidians in the family Botryllidae are the only chordates known to be capable of whole body regeneration (WBR). WBR may occur following the artificial removal of zooids and buds, leaving behind ampullar fragments that may ultimately lead to production of new functional zooids. Prior work on botryllid WBR has relied on laboratory assays, primed by application of retinoic acid, and aimed at elucidating intrinsic differences in mechanism through morphological observations. We compared the regenerative abilities of three botryllid species (Botryllus schlosseri, Botrylloides violaceus, and Botrylloides sp.) at three separate locations in San Francisco Bay. All three species were successful in regenerating complete zooids from ampullar fragments in the field without exogenous application of retinoic acid; however, success rate varied among sites and species. B. violaceus had significantly lower success overall with complete regeneration occurring at only one site. Conversely, B. schlosseri and Botrylloides sp. showed success at both early and later stages at all three sites. Mean time to regeneration for successful individuals was significantly longer between B. violaceus and the other two species and field regeneration times were longer than published laboratory studies with RA. This study shows that WBR occurs in the field and varies among species and populations, thus potentially affecting population viability following disruptive processes such as predation, senescence, or intentional human removal.