When manimals attack!

Apparently the President's dire warnings about "human-animal hybrids" aren't as fanciful as most might have thought - scientists are busy making all sorts of chimeras as you read this. But that doesn't mean we should be worried:

...a team of researchers has inserted a complete human chromosome 21 into mouse embryonic stem cells, and from those generated a line of aneuploid mice that have many of the symptoms of Down syndrome, including the heart defects. They also have problems in spatial learning and memory that have been traced back to defects in long-term potentiation in the central nervous system.

These mice are a tool to help us understand a debilitating human problem.

Sounds like science gone awry to me!