The recombination of man and beast

Slate Magazine: By William Saletan

If you've been laughing at those Neanderthal presidential candidates who still don't believe in evolution, it's time to sober up. Every serious scientist knows we evolved from animals. The question now is whether to put our DNA and theirs back together.

We've been putting baboon hearts, pig valves, and other animal parts in people for decades. We've derived stem cells by inserting human genomes in rabbit eggs. We've made mice with human prostate glands. We've made sheep with nearly half-human livers. This week, Britain's Academy of Medical Sciences reported that scientists have created "thousands of examples of transgenic animals" carrying human DNA. According to the report, "the introduction of human gene sequences into mouse cells in vitro is a technique now practiced in virtually every biomedical research institution across the world." ...

So far, our mixtures are modest. To make humanized animals really creepy, you'd have to do several things. You'd increase the ratio of human to animal DNA. You'd transplant human cells that spread throughout the body. You'd do it early in embryonic development, so the human cells would shape the animals' architecture, not just blend in. You'd grow the embryos to maturity. And you'd start messing with the brain.

We're doing all of those things. ...

We're not doing these things because they're creepy. We're doing them because they're logical. The more you humanize animals, the better they serve their purpose as lab models of humanity. That's what's scary about species mixing. It's not some crazy Frankenstein project. It's the future of medicine.

Now comes the brain. ...

When Stanford's ethicists first heard the proposal for humanized mouse brains, they were grossed out. But after thinking it over, they tentatively endorsed the idea and decided that it might not be bad to endow mice with "some aspects of human consciousness or some human cognitive abilities." The British academy and the U.S. National Academy of Sciences have likewise refused to permanently restrict the humanization of animals. ...

I'll be posting a link to the bioethics article...