Xenopus laevis

The African clawed toed frog Xenopus laevis daudin is an important model organism in developmental biology. While it is not blessed with the short generation time and genetic simplicity found in many model organisms it does have a large and easily manipulable embryo. This ease of manipulation in amphibian embryos has given them an important place in both historical and modern developmental biology.

Xenopus are also notable as having been a standard method of pregnancy testing. Human chorionic gonadotrophin[?] is a hormone found in substantial quantities in the urine of pregnant women; when injected into the female X. laevis it induces them to lay eggs.