Scientists believe that 12 400 years ago the extinction of mammoths in America led to a reduction in emissions of methane into the atmosphere. About 15 000 years ago, large herbivores began to disappear and the Americas. Were mammoths became extinct or exterminated by people as a result of climate change - the exact answer does not exist. Many scientists believe that the extinction of influence of factors, some of them have not yet been identified.
The consequences of the disappearance of large herbivores, however, are available in the official documents. In May 2010 a group of American researchers suggested that the extinction of large herbivores to a large extent affected the cooling of the climate.
Scientists at the University of New Mexico, led by Felissoy Smith suggested that the freezing of many plant species 12,800 years ago can be explained by a decrease in volume of methane in the atmosphere, which was previously produced by herbivores.
But scientists are careful to conclusions. Opponents of the theory believe that the allocation
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this gas representatives of megafauna was not sufficient to trigger global warming, in spite of their large number and a large body mass.
The extinction of megafauna, most likely, this is the first accident that is related to human activity - the conclusion made by some researchers. Later people moved en masse to the United States that occurred 13,400 years ago, and marked the beginning of Quaternary age.
Freezing blood
Several years ago, an international team of researchers succeeded in synthesizing hemoglobin based on DNA extracted from the remains of a mammoth. They proved that the blood oxygen prehistoric animals kept at low temperatures.
It is not Jurassic Park, but like its beginning - a team of researchers was able to restore the blood of mammoth DNA extracted from animal bone material, which disappeared 10,000 years ago. Experimental saga has been going on for nearly seven years, and it gradually explains how prehistoric mammoth adapted to winters in what is now Siberia and North America. His blood did not need to be warm, to perform the main function - to deliver oxygen to the organs.
A little bit crazy idea to allocate a mammoth hemoglobin appeared at the Australian Professor Campbell, a biologist of the University of Adelaide, which is then published their study in the journal Nature Genetics. As the scientists were able to do it? First, it was necessary to extract DNA from the bones, which were under the ice more than 20 000 years. Then we had to find the zone, which is responsible for the synthesis of hemoglobin
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and transform it into RNA. Thereafter, it was necessary to introduce the RNA into the bacterium Escherichia Coli, which may itself be synthesized protein associated with RNA structure. This technique has long been used to produce human insulin
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.
Each of these stages is a kind of scientific challenges posed by the representatives of seven countries - Australia, Canada, Japan, USA, Germany, England and Denmark. And to confirm the success of this study, it is necessary that the experience has been successful cloning of the mammoth.
Cloning a mammoth - Japanese scientists call
Is it possible to resurrect extinct animals entirely, which include mammoths? Scientists hope to do this by maintaining the DNA in a mammoth egg elephant. Nevertheless, technical obstacles are many.
Author of the book "Jurassic Park" Michael Crichton believes that someday technological advances make it possible. If the distortion of the DNA over time, making it impossible to resurrect dinosaurs, as planned, scientists, experts from Japan are sure that experiment will mammoths. Researchers hope to extract DNA from samples which have been frozen for several thousand years ago. Japanese scientists have called for the cooperation of experts on Russian mammoth and two American experts on fertilization in vitro, which will help in the implementation of this crazy project.
Stages of the cloning process assumes the following:
- Get mammoth genetic material
In the late nineties, a lot of researchers have tried to remove the cell nucleus of cells found the remains of mammoths. But the technique that was used then did not allow to carry out a successful cloning experiment, the more that material has been damaged by time or cold. In 2008, the Japanese group led by Dr. Wakayama successfully cloned a mouse, based on the cell material that has been frozen for sixteen years. This experience inspired a professor at Kyoto University Akira Iritani re-launch the project to clone a mammoth. At the moment he is in search of material from a mammoth that is frozen soon after death, to be able to apply the technique of Wakayama.
- Enter the cell nucleus in stem cells of an elephant
To grow the cells of a mammoth, you must enter the cell nucleus of his material in stem cells of an elephant. This step will provide a certain number of cell nuclei, which are necessary for the other stages. But no one can guarantee that the cells will take root in the body of a mammoth elephant.
First of all, you need to extract the egg of an elephant. But at the moment it is impossible to conduct such an operation on a live animal due to the specific location of the reproductive system, experts are planning to do this with a dead elephant. But ovulation
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elephants occur every five or six years, and this is the difficulty, and the possibility that ovulation can happen right before his death, is small.
- Transplanted the embryos into the body of an elephant
If all previous steps are successful, there is transplanted the embryo into the uterus of a female elephant. But nobody knows Whether or not the embryo of a mammoth in the body of an elephant, and if they take root, then you will be able to evolve from a real mammoth.
What then?
The question arises - what to do if cloning is successful, and the earth will reappear mammoths? Do people know how it is necessary to keep an animal, and such as to provide them with adequate nutrition? Do I need to show to the public or to leave the animal access to only a scientist, so as not to disturb him? How will the reproduction of new species? These questions remain open. In addition, there are technical obstacles to the implementation of the project. But Japanese experts optimistic about these difficulties and plan to have five years to get a live mammoth.
