Animal Cloning Not Progressing Very Fast

It has been more than ten years since Dolly was cloned. Yet, for all of the animal cloning that has gone on, apparently the science of somatic cell nuclear transfer has not progressed very far. An article in Science by Jose Cibelli, formerly of Advanced Cell Technology and now a professor in Michigan, details that scientists are having a dickens of a time understanding somatic cell nuclear transfer and making it more efficiently in animals. There is no link to the article, but here are a few quotes:

Ten years ago, Ian Wilmut, Keith Campbell, and their colleagues from the Roslin Institute in Scotland announced the first cloned adult mammal—a sheep named Dolly—using a technique called somatic cell nuclear transfer (1). Since then, the experiment has been independently replicated in 16 other mammalian species. Laboratories around the world launched efforts to identify the mechanism responsible for this phenomenon. Hundreds of peer-reviewed manuscripts later, we are left with many unanswered questions about the technique and are still unable to substantially increase its efficiency. For all species cloned by this method, less than 10% of embryos transferred into the uterus will produce a healthy clone. Why?...

Ten years have not been enough time, though; the long list of unanswered questions about animal cloning reflects how our understanding is stalled at a fundamental level....Are we closer today to finding the mechanism(s) responsible for somatic cell nuclear transfer? Yes, but not by much.

Finding the gene(s) responsible for reprogramming will mark a crucial turning point for this technique in the next decade of animal-cloning research...Unveiling the genes and pathways involved in the cloning procedure is the first step to creating reasonable approaches for generating human cells that can later be used in therapy. Only then will so-called (and still hypothetical) therapeutic cloning become obsolete.

So, what does this mean? Cibelli seems to be stating that successful human cloning for stem cells may be a very long way off because even in animals, which have been cloned for more than ten years, scientists still don’t really understand how it works. He also seems to believe that cloning research may be best used for learning which genes control development, which could allow “reprogramming,” e.g., reverting a normal cell into an embryonic state—which is one of the many exciting “alternatives” to ESCR. In any it certainly appears that regardless of the substantial ethical issues, SCNT in humans may prove a very impractical road to devising efficacious medical therapies—and this dawning understanding is beginning to appear in the scientific literature—although not in politicians’ speeches or popular media reporting.