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Current Research

At present our research is focussed on a severely affected frog, the mink frog, from a site in Minnesota. We have found that the anatomy of the deformed frogs is very predictable. One of the most consistent abnormalities is also one that is almost unique to deformed frogs. Any of the limb long bones can be affected and can become folded into bony triangles:

This is a skeletal preparation of a leg from a deformed frog. In addition to having duplicated bones, a false 'knee' can be seen. The ends of the bones are adjacent, and the center of the bones form the apex of a triangle.

This specific anatomical defect has been seen before in animals treated experimentally with retinoids:

In this experiment, Maden treated developing frogs with retinoids at an early stage of limb development.

We are interested in finding out the types of retinoids capable of causing this result and the molecular changes that lead to the malformations. In addition, samples from the affected site are being tested in the lab for their ability to cause limb defects.

The molecular mechanisms of developmental processes are highly conserved between animals. Hence, the results of these studies will help us assess the possible implications of environmental agents that can cause limb abnormalities in frogs for the health of both wildlife and of humans.

Deformed frogs

Background

Annotated Bibliography

Other Links about Deformed Frogs

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