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Frogs: Princely models for science
As this early Xenopus embryo develops, you can see cells divide and begin to assume a bit of order.

A pondful of uses
The frog’s contribution to science goes beyond its egg. Scientists watch developing Xenopus embryos to learn how tissues differentiate, and study metamorphosing tadpoles to gain insight into how organs are formed. Both of these paths may lead to a better understanding of how to create medical applications for human organ or tissue generation. Researchers also use developing frog embryos to understand the mechanisms underlying vertebrate body plans; they use tadpoles to look at formation of the nervous system; and the list goes on.

Despite all its contributions to basic research, Xenopus laevis isn’t the best model for studying genetics, because of its unique chromosome arrangement: Each cell has four copies of each chromosome rather than the single pair common for humans and other animals (This four-copy arrangement is called tetraploidy, a geneticist’s nightmare!). However, the single-paired genome of a close frog relative, Xenopus tropicalis is currently being sequenced. It has many of the same advantages of its claw-footed cousin, but will be an easier model for genetic research. So Xenopus will continue to contribute to our knowledge for years to come.

Vive les grenouilles! Long live the frog!
The process of metamorphosis, in which tadpoles transform into adult frogs, is one of the most fascinating feats in the biological world. In this movie, notice the tiny legs that are forming. These legs are among the first signs of transformation to the adult form.