For more than 150 years scientists have primarily relied on fossilized bones and teeth to reconstruct creatures from deep time. Skeletons divulge the sizes and shapes of long-ago animals; muscle markings on bones indicate how brawny the creatures were and how they may have moved; tooth shape and wear attest to the kinds of food eaten. All in all, researchers have managed to extract extraordinary quantities of information from these hard parts. On rare occasions, they have chanced on exquisitely preserved mummies and frozen carcasses that have allowed them to add more detail to their reconstructions, such as the length of the fur, the shape of the ears, the specific contents of an animal's last supper. Yet for all that scientists have been able to deduce about the physical characteristics of life-forms from past eras, we know very little about the physiological processes that sustained them.

That gap is closing, however. Recent advances in biotechnology now allow us to reassemble ancient genes from extinct animals and resurrect the proteins those genes encode—proteins that both form and drive the cellular machinery that underlies life-giving processes. The work heralds the dawn of a thrilling new scientific discipline: paleophysiology, the study of how the bodies of bygone organisms functioned in life. We are still in the earliest days of this research, but already we have gained stunning insights into how one iconic beast of prehistory—the woolly mammoth—adapted to the brutal conditions of its Ice Age world. Although the Jurassic Park dream of cloning prehistoric animals remains out of reach, our work has demonstrated the feasibility of observing key physiological processes that took place in creatures that have long since vanished from the face of the earth.

2 Comments

1. 1. Bill_Crofut 05:17 PM 7/20/12

   If the information available to me is correct, the woolly mammoth did not adapt to an ice age. The woolly mammoth is found preserved in ice, frozen in the Siberian permafrost (as an example), some in a kneeling position, some with undigested tropical vegetation in the stomach. That would not seem to indicate adaptation but, rather, death after being rapidly frozen in what, from all indications, was a tropical or semi-tropical habitat. Is the information available to me correct?

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2. 2. jgrosay 05:43 PM 7/20/12

   I vaguely remember having read that even today, the transition from fall to very cold weather in Siberia is very fast, something like a sudden wind, and a tenths of grades temperature drop comes in minutes, this may have happened before in a more severe way for reasons not yet fully understood. The proposal of Jurassic park to clone extinct animals by introducing its DNA in an egg of a living related animal with its nucleus extracted has an almost insurmountable barrier: mitochondria, essential organelles for the energy metabolism of all animal cells, do have part of its DNA inside them as a circular chromosome like in their putative bacterial ancestors, but many other of the genes that regulate build-up and function of mitochondria are transferred to the nucleus of cells, so it would be impossible to find the right combination of nuclear and mitochondrial genes to have the whole system working again, anyway, dreaming is free..

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