15,000 years ago, North America was close to unrecognizable. Most of modern-day Canada and parts of what is now the United States were covered by glaciers and temperatures elsewhere easily averaged below freezing. In the midwest, enormous mammals and birds reigned supreme. One of the most well-known of these massive species was the wooly mammoth. Their stature is believed to have been comparable to today's elephants; however, their hind legs were significantly shorter than their front legs, their colossal ivory tusks often measured over 13 feet in length, and, as you may have guessed, they were exceptionally hairy. Now, Japanese scientists have hatched a plan to bring this ancient beast back to life.
Back in 1996, researchers shocked the world when they unveiled Dolly, the very first test-tube ewe. Dolly lived to be six years old, and has long been hailed as the ultimate triumph of biotechnology. But can the same be done with an extinct species from the last ice age? Allegedly yes, through the process of somatic cell nuclear transfer (SCNT).
In SCNT, scientists extract an egg cell from a live animal and remove its nucleus, replacing it with the nucleus of a somatic cell (a somatic cell is any cell not from a sex organ). Somatic cells are diploid cells, meaning that they have two copies of genetic material from the parent animals. Germ cells, such as egg cells, are called haploid because they only have one copy. Replacing the nuclear material from an egg cell with that of a somatic cell is therefore an effective simulation of fertilization. Once the egg has been modified, it can then be implanted in a surrogate uterus, where it divides to form an embryo.
The research team hopes to isolate an intact somatic cell from frozen remains of a wooly mammoth. Within five or six years, they plan to successfully replace the nucleus of an elephant's egg cell with the nucleus of this preserved mammoth cell, implant it into the uterus of an elephant, and wait patiently for the birth of an animal that has not existed since humanity's first predecessors roamed the earth. No sweat. For some biologists, raising the dead is all in a day's work.