More like Planet of the Mice.
A "friendly competition" between Varki's lab and counterparts in Japan is therefore teasing out the consequences, for anatomy and behavior, of mice prompted to produce only the human form of sialic acid (the Japanese group — using mice modified to have the same gene deletion that results in humans producing only Neu5Ac) or transgenic mice raised to overexpress the enzyme that leads to Neu5Gc production in the brain (Varki's group).