Zitat des Tages von John Gurdon:
The aim of a nuclear-transplant experiment is to insert the nucleus of a specialized cell into an unfertilized egg whose nucleus has been removed.
I think that I cannot immediately see the route by which we should really understand memory and the workings of the brain.
I must have been born with a strong attraction toward, and possibly even an aptitude for, doing things on a small scale.
My first attempts to transplant nuclei in Xenopus were completely unsuccessful, because the Xenopus egg, unlike those of other amphibians, is surrounded by an extremely elastic membrane and jelly layer that make penetration by a micropipette impossible.
Shinya Yamanaka's work has involved mice and human cells, and advances the prospect of providing new cells or body parts for patients.
The importance of the egg's non-nuclear material - the cytoplasm - in early development is apparent in the consistent relation that is seen to exist between certain regions in the cytoplasm of a fertilized egg and certain kinds or directions of cell differentiation.
I myself have been a major beneficiary of the view that no animal will more repay treatment that is kind and fair.
Nuclear transplantation is a technique that has enormously facilitated the analysis of these interactions between nucleus and cytoplasm.
I wondered whether the nuclear transfer techniques could be used to introduce purified macro-molecules into an egg, and hence into embryonic cells.
I remember that, at an early age, I spent many months making a three-masted sailing boat with rigging in a half-walnut shell.
I get into lab early and leave a bit early, too. So I like to have an hour or two before everybody comes in.
If you took some famous religious leader, for example, and said it would be nice to clone them indefinitely so you have a dynasty of leaders, my own guess would be that each time the cloning takes place, they would become more and more defective, presumably mentally defective and subsequently worse.
For my part, I have worked all my life with eggs and embryos of frogs. Compared to other small animals, these have figured prominently in the world of literature.
Within six months of starting my Ph.D. work in 1956, I had already obtained feeding tadpoles derived from transplanted nuclei of embryonic cells.
It's a very complex network of genes making products which go into the nucleus and turn on other genes. And, in fact, you find a continuing network of processes going on in a very complex way by which genes are subject to these continual adjustments, as you might say - the computer programmer deciding which genes ultimately will work.
It is particularly pleasing to see how purely basic research, originally aimed at testing the genetic identity of different cell types in the body, has turned out to have clear human health prospects.
There's a danger of some of the best people saying, 'I don't want a career in science.'
The earliest example known to me of replaced body parts is exemplified by a Mayan skull dating back to 1400 BC. In this skull, false teeth made of stone had been implanted.
