Decoupling of fission and regenerative capabilities in an asexual oligochaete
Bely, A.E. (1999). Decoupling of fission and regenerative capabilities in an asexual oligochaete, in: Healy, B.M. et al. Aquatic Oligochaetes: Proceedings of the 7th International Symposium on Aquatic Oligochaetes held in Presque Isle, Maine, USA, 18-22 August 1997. Developments in Hydrobiology, 139: pp. 243-251. https://dx.doi.org/10.1007/978-94-011-4207-6_24 In: Healy, B.M.; Reynoldson, T.B.; Coates, K.A. (Ed.) (1999). Aquatic Oligochaetes: Proceedings of the 7th International Symposium on Aquatic Oligochaetes held in Presque Isle, Maine, USA, 18-22 August 1997. Reprinted from Hydrobiologia, vol. 406. Developments in Hydrobiology, 139. Springer Science+Business Media: Dordrecht. ISBN 978-94-010-5829-2; e-ISBN 978-94-011-4207-6. XIV, 290 pp. https://dx.doi.org/10.1007/978-94-011-4207-6, more In: Dumont, H.J. (Ed.) Developments in Hydrobiology. Kluwer Academic/Springer: The Hague; London; Boston; Dordrecht. ISSN 0167-8418, more |
| Abstract | Agametic reproduction by fission has evolved numerous times in the Annelida. In this group, as well as others, the developmental processes of fission appear to be based on those of regeneration. Thus far, all fissiparous annelids whose regenerative abilities have been investigated fully are capable of regenerating both anteriorly and posteriorly. However, in this paper, I describe a unique exception to this association between fission and regenerative abilities. Regeneration experiments demonstrate that the fissiparous annelid Paranais litoralis (Oligochaeta: Naididae) has lost the capacity for full anterior regeneration. The four anterior segments of P. litoralis are produced routinely during each round of fission, yet this species is incapable of producing these same segments by anterior regeneration. I propose that fissiparous reproduction, possibly coupled with a low susceptibility to amputation in nature, may have relaxed selection for anterior regeneration in P. litoralis. The decoupling of fission and regenerative abilities suggests that some steps in the developmental trajectories that lead to fission and regeneration may have diverged in this species. |
|
