I’ve worked with DNA for decades and it comes as shock when someone generates a living animal from the equivalent of those peas that float around the bottom of your freezer! A mouse that had sat in a freezer 16 years with no preservatives has genetic material intact enough for researchers to use the cloning technique to create a living cell and from there, a mouse.
Just how the DNA survived the rigours of being frozen, something that is usually guaranteed to sheer and destroy these long biomolecules, is unknown.
As is usual with cloning, the report has induced wild speculation about resurrecting the mammoth from Siberian frozen tissues, even though analyses of DNA from extinct organisms such as dodos, frozen mammoths, bears and even Neanderthal teeth, has only ever found DNA degraded into billions of small pieces and well beyond resurrection.
Having said that, I wonder whether anyone has actually looked in frozen tissues, rather than assume the DNA is all degraded and simply extract it biochemically, a process which sheers it to bits anyway. Of course the other critical stages in cloning are the recipient egg and the mother to carry the embryo, so if someone is really going to try and resurrect a mammoth then I guess the world’s elephant reproductive biologists had better step forward.
Mammoth calf preserved in permafrost, on display in St Petersburg museum
It is a fascinating development and one that is likely to find interesting future applications. But two messages.
First, don’t take these findings as a go ahead to ignore those little snowflakes on the frozen pizza that tell you to only keep it three months (food poisoning is not fun).
Second, when you’re next cleaning-out the freezer, if you do find a frozen extinct animal rolling around with the peas then keep it safe; you might be able to supply some lab with the next scientific breakthrough.
Find out more
'Production of healthy cloned mice from bodies frozen at -20°C for 16 years'
by Sayaka Wakayama, Hiroshi Ohta, Takafusa Hikichi, Eiji Mizutani, Takamasa Iwaki, Osami Kanagawa, and Teruhiko Wakayama.
Published in PNAS, 11th November 2008