IT IS STRIKING just how little we know about human development, especially given we are now decades into the modern era of biology. How is it possible that we understand exquisitely well how worms, fruit flies, and rodents develop, but our own species’ development remains a black box?
While this is not really blue sky it does suggest a real progression in the science. This line of enquiry does raise similar issues that were addressed when recombinant DNA research began.
Human chimeras are mixtures of human cells with rodent, pig, or other animal embryos. It is important to note that this research does not directly use human embryos or fetuses, instead relying on pluripotent stem cells, which can be taken from a person’s skin and genetically engineered to be pluripotent—meaning they can develop into nearly any cell type. Human chimeras have great potential to enhance our understanding of human development. Among other things, this kind of work could lead to discoveries about human brain development, a fascinating, but scientifically very challenging area of study. Human chimera work could also shed new light on serious human developmental problems, and even be used to manufacture donor organs—if chimeric embryos are allowed to develop into fetuses…