One-Eyed Tadpole

Asked January 29, 2018, 9:58 AM EST

I have some tadpoles I saved from my pool and I noticed that one is developing with just one eye. The right eye appears to be perfectly normal, but there's nothing but smooth skin over the area where the left should be. I'm not sure of species yet, though I know they're treefrogs of some variety. Aside from the eye deformity, everything else seems to be in normal proportion, though this one is way behind his/her brothers and sisters in development (legs haven't begun to sprout) and much larger (at least 2-3 times the size of the largest individual). I don't believe this is different species, as they all came from the same clutch of eggs. They've also shared a tank since a day after hatching, so they should be responding to the same environmental factors (predator cues, water levels, temperatures, etc.). Is there anything in particular I should be looking for as this tadpole develops, or is there any scientific value to observing the process?

Seminole County Florida

1 Response

Thank you for your question.

It sounds as if this is not a case of injury; rather just a genetic mutation. The smooth skin is my clue. Plus it sounds like you do a lot of observation and seems you would have noticed a wound.

Tadpoles have stem cells that express a set of transcription factors (proteins that trigger expression of other genes) that are known to regulate eye development. In this case it is likely that transcription was not expressed.

With only one eye the tadpole may not swim efficiently and if it develops into a frog it may have problems catching pray as its depth perception will be off. Donald House with the Department of Computer Science at Williams College has been study monocular and binocular vision in frogs and toads. You might want to read his work if interested.

There is always scientific value in keeping notes on biological processes. I have been doing it for years and do not know if it will lead to anything but you never can tell.

Good luck and thank you for sharing.