Penny and I were out walking with Jabari and her mum today and we were discussing the news that puppies have been produced by cloning. I said that it would be wonderful to have an exact copy of Penny - it seems to me that only cloning would replicate the unique series of events that produced this beloved dog. She is a mixed breed of basically unknown ancestry, so even if we had not had her neutered, any puppies she produced would most probably not have been like her.
Jabari's mum said that even a cloned dog is not a copy of the parent - in other words, it will have different life experiences from the original dog. She also maintained that it's impossible to ever know for sure that cloned individuals are in fact identical in every way - temperament, for instance. This is an interesting question that has been debated for years by philosphers and psychologists. Hundreds of studies of human identical twins have debated the 'nature versus nurture' question. Just how much are our life experiences and reactions - or those of our dogs - determined by genetic inheritance? I've heard the comment made that even if twins share the same DNA and placenta, there are differences in experiences. One is born before the other, for a start. Each has a the other, different twin to live with throughout life.
In humans, if two or more children are born at the same time, we call them twins and consider it a somewhat unusual situation. If they are then found to be identical twins, it's more unusual. However, dogs routinely give birth to sets of babies, so we don't consider the puppies anything other than routine 'litter mates'. I've found reference to at least one case where it was assumed that two puppies with similar markings were probably identical twins.
There's also a discussion at a blog called AnswerGirl about identical twinning in dogs. One of the commenters says that she feels sure she has identical twins because she saw the birth and two of the puppies came out of the same sac. It's interesting that AnswerGirl said she has two (human!) identical twin sisters and it has always been easy to tell them apart because "various environmental factors can make them look slightly different from each other, just as with humans."
I recently taught two children who were identical twins. It was fun to listen to them finish off each other's sentences. It seemed as if they each knew what the other would say before she started speaking. However, they looked very different. One was smaller and less sturdy-looking. She cheerfully said that her sister had 'stolen her food' in the womb and if they hadn't been born when they were, she would have soon died.
When I looked at the video clip of the puppies (who have been produced at a cost of more than two million dollars, if I understood the reporter), I thought they were beautiful, but I wondered if we have the right to play with nature this way. By the way, I got the address for the video in an email from Dr Jon at PetPlace.com.
It makes me think back to the fuss when 'Snuppy' was reportedly cloned in South Korea in 2005. When the scientist was discovered to have faked some of his research in other areas, some wondered whether Snuppy was in fact a kind of identical twin, produced by a technique called embryo splitting. One might have been frozen and produced later to seem like a clone of the other twin. Many reports produced by a Google search on this topic say that Nature magazine was to conduct a study to check the results but I can't see any sites that say whether it in fact happened.
Interestingly, there is a report that two puppies were due to be born around now, after Snuffy impregnated two other cloned dogs. Reports say it was by artificial insemination.
It all sounds incredibly complex, expensive and strangely unethical, to me. I think I'll just enjoy the one and only Penny...