Many scientists have considered using cloning to resurrect extinct animals frozen in permafrost, such as the woolly mammoth. This has proven to be difficult because there are no live cells, and DNA is irreparably damaged by ice crystals.
Now cloning techniques may have progressed to the point where resurrection from permafrost could become reality. Teruhiko Wakayama at the RIKEN Center for Developmental Biology in Kobe and co-workers have produced healthy cloned mice from cells that were frozen for 16 years at -20 °C without any preserving chemicals—simulating the conditions in permafrost (1).
Wakayama and his team adapted a common cloning technique called somatic cell nuclear transfer (SCNT). Usually, researchers collect a single live cell of the donor animal and fuse it with a living egg that has had its own nucleus removed. However dead cells cannot be used for cell fusion, so Wakayama invented a new injection method in which the nuclei from dead cells are directly injected into the egg.
The researchers first performed SCNT on cells from mice frozen for a week. They found that frozen brain cells were the best donor nuclei and, surprisingly, the frozen cell nuclei yielded more healthy clones than living brain cells. It is possible that all the sugars in the brain protect cells from freezing damage. Furthermore, the freezing process might partly unravel the tight bundle of nuclear DNA, allowing the host egg to access the donor’s genetic code more easily.
The normal SCNT procedure failed to produce cloned mice from bodies frozen for 16 years, but the researchers managed to establish embryonic stem cell lines. The stem cell nuclei were injected into other eggs and transferred into surrogate mothers, leading to four healthy cloned mice.
This work represents the first successful cloning from bodies stored in conditions similar to the natural permafrost environment. Wakayama is hopeful that they could eventually produce clones from ancient bodies of extinct species such as mammoths.
“Cells frozen in permafrost for thousands of years are not only frozen but also dried out,” he explains. “This means there is probably more damage in the nuclei than in our 16-year-frozen cells. However, we already published results this year in which we succeeded in using freeze-dried cells for nuclear transfer (2).
“What’s more, our paper demonstrated that even blood cells can be used as nuclear donors. Blood cells are found in any tissue, including skin and bones, which are most likely to be found in permafrost.”
1. Wakayama, S., Ohta, H., Hikichi, T., Mizutani, E., Iwaki, T., Kanagawa, O. & Wakayama, T. Production of healthy cloned mice from bodies frozen at -20 °C for 16 years. Proceedings of the National Academy of Sciences 105, 17318–17322 (2008).
2. Ono, T., Mizutani, E., Li, C. & Wakayama, T. Nuclear transfer preserves the nuclear genome of freeze-dried mouse cells. The Journal of Reproduction and Development In press. (2008)
The corresponding author for this highlight is based at the RIKEN Laboratory for Genomic Reprogramming
Saeko Okada | ResearchSEA
Maelstroms in the heart
22.02.2018 | Max-Planck-Institut für Dynamik und Selbstorganisation
Decoding the structure of the huntingtin protein
22.02.2018 | Max-Planck-Institut für Biochemie
Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.
But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...
Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.
The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
22.02.2018 | Life Sciences
22.02.2018 | Information Technology
22.02.2018 | Health and Medicine