A fraction of 28,0000 years old thick mammoth cell components were recently "woken up" for a short period of time in a new experiment, but clone of ice animals is still far away.
experiments, researchers took the cells from Yuka, a mummy mammoth mummy ( Mammuthus primigenius ) whose remains were discovered in the permafrost of Siberian in 2011. Then, scientists did not at least a damaged nucleus (structures that contain genetic material) from each cell and bless the nuclei in mouseheads.
Initially, this scheme has "activated" mammoth chamomens, as some biological reactions have occurred before cell division actually occurs within the mouse cell. But these reactions soon came to a crash stopped, perhaps, in part, because the mammoth DNA was severely damaged after spending 28,000 years buried in the permafrost, researchers said. [In Photos: Mummified Woolly Mammoth Discovered]
But why did researchers put mammoth DNA into mouseheads? The answer relates to the ability of an egg to replicate DNA and divide into more cells.
"Eggs have all life cellular machinery that you may need to correct error correction and repair damage that occurs within the nucleus," said Beth Shapiro, an ecology professor and evolutionary biology at the University of California, Santa Cruz, who were not involved in the study. "[The scientists] was really stuck [the mammoth nuclei] there and said, 'All right, cellular machinery, do your thing.'"
And, at first, cellular machinery is trying to repair the damaged DNA within chromosomes and pieces together broken bits, Shapiro said. "But [the egg] can only be done," he said in Live Science. "When the nucleus is damaged, then it is not possible to reconstitute it with what you need to do to actually restore it to life." As a result, no mouse-mammoth hybrid cells enter the cell division, one step needed to create an embryo and, perhaps one day, clone a mammoth.
"The results presented here clearly show us the impossible de facto again to clone the mammoth through the current NT technology [nuclear-transfer]. Researchers wrote, published online March 1
Put another way, "a clear demonstration that this technique will not work to clone a mammoth," Shapiro says. "Cells are also damaged."
Once the mammoth died, its DNA began to be destructive, because bacteria from the mammoth gut and the surrounding environment began to muffle the dead mammoth cells. Ultraviolet (UV) radiation As a result, DNA fragments of the nucleus survived to date can be just ten in hundreds of bases long, in terms of ip the millions found in the DNA of modern elephants, Shapiro said.
However, the study is still moving, said Rebekah Rogers, an assistant professor of bioinformatics at the University of North Carolina at Charlotte, who did not involve research. For example, if researchers can insert even small fragments of mammoth DNA into a cell line, which can reveal what DNA is doing in a living entity, he said. In the study, researchers added that "our approach paves the way for analyzing biological activities of nuclei in dead animal species."
However, Rogers said he wanted to see more evidence that mammoth The chromosomes actually made it in the mouse. "It's possible that you can have a highly modified mouse chromosome or potentially other DNA contamination," he says. "They have an extraordinary claim that they have put mammoth chromosomes on a mouse [egg]. I really want to see many proofs for this type of claim."
Other research groups are also trying to revive the mammoth, using other technologies. George Church, a geneticist at Harvard University and the Massachusetts Institute of Technology who heads the Harvard Woolly Mammoth Revival team, takes a strategy. He uses CRISPR – a tool that can edit bases, or letters of DNA – to insert narrow mammoth DNA genes of Asian elephants, closely related to dead animals.
"They are not trying to revive a mammoth genome," Shapiro says. "They try to create one by adjusting an elephant's genome, so they can have a living cell as an end product."
However, bringing back animals at the ice age is controversial. Many conservationists have indicated that resources should be spent on current threatened or endangered animals rather than animals that have died in the past.
Originally published at Live Science .