Go into any comic shop and you will see a plethora of human-animal hybrid heroes and heroines: Batman, Spiderman, Catwoman, et al.

Out in the real world, fusing human and animal characteristics took a major knock this week.

Stem cell scientists have long sought ways to create patient-specific cells with the potency and growth characteristics of embryonic stem cells. One method (in theory at least) to achieve that would be to introduce the nucleus from a patient’s cell into an enucleated human egg. These hybrid cells could be used to develop large numbers of whatever cell type the patient needs replaced.

Due to a boatload of ethical and practical issues, gaining access to a supply of human eggs for this purpose is almost impossible, so scientists have turned to non-human species as egg donors.

With the possible exception of science fiction devotees, many people react to the prospect of human-animal hybrids with squeamishness or frank outrage. It’s a challenge to find anyone who has a rosy feeling about human-bovine hybrids, even if they are a stepping-stone to cures for serious diseases (as their promoters assert).

Well worry no more! Robert Lanza and colleagues have recently proven what many intuitively know: that human nuclei and non-human eggs just don’t get along. The problem appears to be a lack of communication between the animal egg and human donor nucleus. The lack of crosstalk leads to down-regulation of the genes needed for pluripotency and blocks development.

As a scientist myself, I know that one thing we excel at is unleashing mysterious forces we cannot control. Luckily this one didn’t make it out of the starting gate.

John McCulloch

John provides assistance to life sciences entrepreneurs in business strategy, management, intellectual property, financing and licensing. See more…