In the film Jurassic Park, a scientist learned to clone dinosaurs and on a desert island created a whole amusement park, in which you could see a living ancient animal. However, the hypothesis about the possibility of cloning dinosaurs from fossil remains, which was so relevant after the release of the movie "Jurassic Park", in the end turned out to be untenable.
Australian scientists led by Morten Allentoft and Michael Buns from Murdoch University (Western Australia) proved that it is impossible to "recreate" a living dinosaur.
In an article published in the Proceedings of the Royal Society, it is said that scientists have determined the rate at which DNA molecules decay.
The researchers carried out radiocarbon dating of bone tissue taken from the fossilized bones of 158 extinct moa birds. These unique and huge birds lived in New Zealand, but 600 years ago they were completely destroyed by the Maori aborigines. As a result of research, scientists have found that the amount of DNA in bone tissue decreases over time - every 521 years, the number of molecules is reduced by half.
The last DNA molecules disappear from the bone tissue after about 6, 8 million years. At the same time, the last dinosaurs disappeared from the face of the earth at the end of the Cretaceous, that is, about 65 million years ago - long before the critical threshold for DNA of 6, 8 million years, and there are no DNA molecules left in the bone tissue of the remains that archaeologists manage to find.
“As a result, we found that the amount of DNA in bone tissue, if kept at a temperature of 13, 1 degrees Celsius, every 521 years is reduced by half, ” - said the head of the research team Mike Bunce.
“We extrapolated this data to other, higher and lower temperatures and found that if you keep the bone tissue at a temperature of minus 5 degrees, the last DNA molecules will disappear in about 6, 8 million years, ” he added.
Long enough fragments of the genome can only be found in frozen bones no more than a million years old.
By the way, to date, the most ancient DNA samples have been isolated from the remains of animals and plants found in permafrost. The age of the found remains is about 500 thousand years.
It is worth noting that scientists will conduct further research in this area, since differences in the age of the remains are responsible for only 38.6% of the discrepancies in the degree of DNA destruction. The rate of DNA decay is influenced by many factors, including the storage conditions of the remains after excavation, the chemical composition of the soil, and even the time of year in which the animal died.
That is, there is a chance that in conditions of eternal ice or underground caves, the half-life of the genetic material will be longer than geneticists assume.
Is it possible to clone a mammoth?
Scientists from the Yakutsk North-Eastern Federal University and the Seoul Center for Stem Cell Research have signed an agreement to work together on cloning a mammoth. Scientists will try to revive the ancient animal using the remains of a mammoth found in permafrost. The mammoth is only about 60, 000 years old and thanks to the cold it is almost completely preserved. For the experiment, a modern Indian elephant was chosen, since its genetic code is as similar as possible to the DNA of mammoths.
According to approximate forecasts of scientists, the results of the experiment will be known no earlier than in 10-20 years.
The topic of human cloning is developing not so much in a scientific way as in a social and ethical one, causing controversy on the topic of biological safety, self-identification of the "new man", the possibility of the appearance of inferior people, giving rise also to religious disputes. At the same time, animal cloning experiments are carried out and have examples of successful completion.
The world's first clone - a tadpole - was created back in 1952. One of the first successful cloning of a mammal was carried out by Soviet researchers back in 1987. It was an ordinary house mouse.
The most striking milestone in the history of cloning of living beings was the birth of Dolly the sheep - this is the first cloned mammal animal obtained by transplanting the nucleus of a somatic cell into the cytoplasm of an egg without its own nucleus. Dolly the sheep was a genetic copy of the donor sheep.
If in natural conditions each organism combines the genetic traits of a father and a mother, then Dolly had only one genetic "parent" - the prototype sheep. The experiment was conducted by Ian Wilmut and Keith Campbell at the Rosslyn Institute in Scotland in 1996 and was a breakthrough in technology.
Later, British and other scientists conducted experiments on the cloning of various mammals, including horses, bulls, cats and dogs.