"They want to create early-stage “chimeric” embryos that would be 99.9 per cent human and 0.1 per cent animal..."
That's a rather misleading statement, and I'm not sure whether or not the Telegraph authors realize it.
About 97% of a human being's DNA content is total rubbish - it's not maintained by error-correcting enzymes, it's not transcoded into messenger RNA, it's not compiled into proteins. It just sort of sits there taking up space. Sure, in some cases the simple act of taking up space might be biochemically useful, but by and large it's just genetic residue.
Of the 3% that actually encodes real, useful, active genes, between 90% to 95% of that material is common among all mammals. It encodes stuff like organ structure, hormones, even super-fundamental stuff like cellular respiration.
The remaining differences are largely tuning parameters - i.e. just how wide to grow the rib cage, at what angle to connect the skull to the spine, exactly how far up the ulna to attach the bicep, and so on. The existence of these tuning parameters is common to almost all mammalian species; the only real variant is the exact settings to which these parameters are set (and variations of these settings exist within a species).
Very, very little DNA actually codes for traits that are distinctly unique to any given species. For humans, for example, the brain structures known as the Werneke's and Broca's areas have no known corrolary anywhere in the animal kingdom. For rabbits, the reflective retinal layer called the tapetum lucidum, while not unique to rabbits, represents an organ that human DNA presumably does not have the code for.
It is differences such as these that constitute the 0.1% that the article describes. However, it fails to mention that, of the 99.9% of the DNA that is "human", about 97% of it is junk while the remaining 3% is actually common to both the human and the animal in question.
Indeed, to be useful, I would think they should express things in terms of "Of the genetic material in the new cells, xx% is uniquely human, yy% is uniquely lapine, zz% is common to both rabids and humans, and ww% appears to be random filler.
I guess this is the end result of acceptance of the theory of evolution. When people get away from the belief that man was created in the image of God and is just another animal that evolved from another animal, anything can be justified.
Scriptural references in Genesis suggest that it was the corruption of the human race by angelic beings that was a factor in God judging the earth and destroying it in the Flood. If mankind is now in the process of corrupting the human race for the second time, they'd best be aware of the danger they're bringing on themselves.