Then there's the issue of imprinting. Mammals carry two copies of each gene: one set from their mother, the other from their father. But only of these copies is active at any one time.
In a clone, "the normal battle between mom and dad" is not taking place, Lanza says. The end result: critical messages from the genes are being lost during an embryo's development, potentially leading to cardiac problems, respiratory ailments and "a messed up placenta".
The hurdles don't end here.
When DNA is in a quiescent state, it looks like spaghetti noodles with proteins attached to it. This means that when the skin cell DNA is sucked out, it's carrying a lot of protein baggage. It is possible these proteins may get in the way of the egg-skin cell DNA fusion.
Researchers at Genetic Saving and Clone say they have solved this problem by using a new technique called chromatin transfer that cleans the DNA. The result, according to Hawthorne, is higher efficiency.
"Our losses are well under 50 per cent," he says, adding that such losses are typical in commercial breeding.
Magnus and other question these claims - scientist at Genetic Saving & Clone have not published their results. But jum Robl, President f South Dakota biotech company called Hematech and one of the developers of chromatin transfer, says he, too, had got good results using this method to clone cows.
Hawthorne says when the process doesn't work it's generally because of an early stage mishap- something that happens before the embryos really develop into animals. As he sees it, "a one-to eight - cell embryo is not a sentient being".
"It doesn't matter if we put 100,000 of these embryos down the sink," he says.
Yet, the battle over pet clones only partially hinges on technical and molecular huddles.
|
