Hannah Waters reports at The Scientist (14th February 2011),
The mouse is not enough
Early embryonic development differs between mice and cows, suggesting mice may not reflect mammalian development as well as scientists had believed
[ … ]
Specifically, the mechanism of cell commitment in early embryos differs between mice and cows, suggesting that development in mice may not be representative of development in other mammals, including humans.
This research suggests “that the mouse alone is not the ideal model if you want to study mammalian embryogenesis,” said Michael Bader, a cardiovascular biologist who works on rat embryogenesis at the Max Delbruck Center for Molecular Medicine in Berlin and was not involved in the research.
Reminds me of the wheeze about the rats flopped in an alley: One explains to the other “I used to work in biomedical research but they fired me because I never got sick the way they expected.”