New research into the amazing fin regeneration powers of Bichirs, (Polypterus spp.) is offering insight into the regenerative powers of ancient vertebrates.
Scientists studied two species of the primitive, eel-like African fish and found that they were capable of re-growing amputated pectoral fins completely in a matter of weeks.
The research paper, published in the Proceedings of the National Academy of Sciences, looked into the processes involved in this remarkable ability, proposing that early vertebrates shared significant limb regeneration abilities during the ancient evolutionary changes from fin to limb.
Limb regeneration in invertebrates is commonplace, but only a few vertebrates can manage the trick and scientists are not only interested in why such a useful ability has been lost but also how it occurred in the first place.
Newts, salamanders and axolotls are amongst the most complex vertebrates capable of varying degrees of limb re-growth and many fish species are able to re-grow lost fins, however the Bichirs' ancient physiology makes it a special case.
Fish such as the much studied Zebra danio (Danio rerio) have fins containing bones mainly related to their specialised, hardened skin but Bichirs' fins have considerably more fleshy tissue as well as a bone structure of the same type as their internal skeleton. This means their regenerative powers could prove invaluable when comparing the differing ways regeneration occurs in vertebrates.
There are currently 17 species of Bichir and Ropefish in the family Polypteridae all found in the freshwaters of Africa and consisting of some of the most primitive ray-finned fish.
The name Polypterus means 'lots of fins' in Greek and refers to their multiple dorsal fin-lets which can number between 5 and 18 depending on species. Bichirs can breath atmospheric air through an adapted swimbladder and young fish have external gills like axolotls which are lost as the fish matures.
For more information see the paper; Rodrigo Cuervo, RocÌo Hern·ndez-MartÌnez, JesË™s Chimal-Monroy, Horacio Merchant-Larios, and Luis Covarrubias, "Full regeneration of the tribasal Polypterus fin"; Proceedings of the National Academy of Sciences, February 21, 2012, doi: 10.1073/pnas.1006619109
You can read more about these amazing fish in the April 2012 issue of PFK.
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