Scientists have undertaken a molecular study of Chinese catfishes to determine how they\
Peng, Zhang, He and Chen of the Institute of Hydrobiology at the Chinese Academy of Sciences sequenced the mitochondrial DNA of the cytochrome b gene of 27 different catfish across 11 familes, including 24 different catfish genera found in China.
To determine how the Chinese catfishes were related to catfishes and other fishes, such as carps and characins, elsewhere in the world, they also tested the DNA of a subset of other fish, then compared the results.
The results showed that all of the Chinese catfishes have evolved from a single ancestor - they form a monophyletic group - and also revealed how the different genera are related to one another.
The Akysidae, Sisoridae and Amblycipitidae species is monophyletic and all evolved from a single ancestor.
Similarly, the Clariidae, Schilbidae, Cranoglanididae, Pangasiidae, Siluridae, Claroteidae and Bagridae (some of which are found across the globe) are all monophyletic, too.
The Cranoglanididae which come from China, and the Ictaluridae which come from North America are closely related sister groups in the evolutionary family tree for catfishes.
The marine catfishes of the Plotosidae family couldn\'t be resolved in this study, so scientists are little closer to finding out what they\'re related to.
For more details see the paper (in Chinese): Peng ZG, Zhang YG, He SP, Chen YY (2005) - Phylogeny of chinese catfishes inferred from mitochondrial cytochrome b sequences. Yi Chuan Xue Bao, Feb ; 32(2): 145-54.