The newest work, at U.C.L.A.'s AIDS Institute, was in mice bred without immune systems in which human thymus cells were implanted and infected.

The "Ak" in Akt was a temporary classification name for a mouse bred and maintained by Jacob Furth that developed spontaneous thymic lymphomas.

Apparently the mice are breeding at a significantly faster rate, but bearing undeveloped fetuses; guinea pigs show similar tendencies.

In a recent study, Lynx collaborators at the University of Pennsylvania worked with mice specially bred to have no immune response, and then exposed them to transplanted human melanoma cells.

The female deer mouse can reproduce at all times of the year, though in most parts of their range deer mice breed from March to October.

In the latest study, which used mice bred to have the disease, Dr. Wakeland found four "suppressor" genes that, when present in the mice, seemed to stop lupus.

In one study, mice bred to not express TLR 11 (knock-out mice) did not mount the IL-12 response upon profilin stimulation.

Calorically restricted mice do not breed at all.

The mice breed throughout the year, giving birth to litters of up to five young, with three or four being typical.

This trait proved to be heritable, and mice bred to be homozygous for the mutation eventually lost all circadian rhythmicity after several days in constant darkness.