A handful of 28,000-year-old woolly cell parts have recently been "awakened" for a short time in a new experiment, but cloning of the ice age is still far from being.
In that experiment, the researchers extracted cells from Yuka, a woolly mother ( Mammuthus primigenius ), whose remains were found in the Siberian permafrost in 2011. Since the sciences, the least-damaged nuclei (structures containing genetic material) were found from each cell and popped the nuclei into mouse eggs.
First, this maneuver held the mammoth chromosomes, since several biological reactions that occurred before cell division actually occurred in the mouse cell. But these reactions soon came to a crash stop, presumably partly, because mammoth DNA was severely damaged after spending 28,000 years buried in permafrost, the researchers said. [In Photos: Mummified Woolly Mammoth Discovered]
But why did the researchers put mammoth DNA into mouse eggs? The answer has to do with an egg's ability to replicate DNA and divide into multiple cells.
"The eggs have all the living cellular machines that you may need to make error correction and fix the damage that has happened within the cores," said Beth Shapiro, a professor of ecology and evolutionary biology at the University of California, Santa Cruz, who was not involved in the study. . "[The scientists] was basically just [the mammoth nuclei] there and said," Okay, mobile machines, do your thing. ""
And primarily, mobile machines tried to fix damaged DNA in the chromosomes and the piece together the broken pieces said Shapiro. "But [the egg] can only do so much," she told Live Science. "When the kernels are badly damaged, it's just not possible to reconstruct this to what you need to do to actually bring it back to life."
As a result, none of the mouse mammalian cells entered cell division, a step necessary to create an embryo and perhaps one day clone a mammoth.
"The results presented here clearly show us the actual impossibility of cloning the mammoth through current NT technology," Scientists wrote in the study, published online on March 1
Another way, "it's a pretty clear demonstration that this approach won't work to clone a mammoth," Shapiro said. "The cells are too damaged".
As soon as the mammoth died, its DNA began to deteriorate. This is because bacteria from the mammoth gut and the environment began to cuddle down on the dead mammoth cells. Ultraviolet (UV) radiation from the sun also broke more of the genetic material, and these processes continued for eons. As a result, DNA fragments in the nucleus that survived to date can only be tens of hundred bases in length, instead of the millions present in the DNA of modern elephants, Shapiro said.
However, the study is still exciting, said Rebekah Rogers, an assistant professor of bioinformatics at the University of North Carolina in Charlotte, who was not involved in the research. For example, if researchers can insert even small fragments of mammoth DNA into a cell line, it can reveal what the DNA does in a living creature, she said. [Mammoth Resurrection: 11 Hurdles to Bringing Back an Ice Age Beast]
In the study, the researchers added that "our approach paves the way for evaluating biological activities of nuclei in extinct animal species".
However, Rogers said she would like to see more evidence that mammoth chromosomes actually did it in the mouse egg. "It is possible that you may get a highly modified mouse chromosome or possibly some other DNA contamination," she said. "They have this extraordinary claim that they put mammographic chromosomes in a mouse [egg]. I would really like to see much evidence for that kind of claim."
Other research groups are also trying to revive the mammoth using other techniques. George Church, a geneticist at Harvard University and the Massachusetts Institute of Technology leading the Harvard Woolly Mammoth Revival team, is taking an approach. He uses CRISPR – a tool that can edit DNA bases or letters – to introduce wool-mature genes into the DNA of Asian elephants, which are closely related to the extinct animals.
"They're not trying to revive a mammoth through, Shapiro said." They are trying to create one by tweaking an elephant genome. That way, they could have a living cell as an end product. "Returning the ice-age is, however, controversial. Many conservationists claim that resources should be spent on present-threatened or endangered animals rather than animals that died away long ago.
Originally published on Live Science .