Scientists have cloned the clone of a clone (and then some).
A team at the RIKEN Center for Developmental Biology in Kobe, Japan have successfully created a 25th generation clone, and all 580 of the cloned offspring emerged healthy and fertile.
Formerly, cloning an animal beyond two or three generations was fraught with difficulties. Often, animals cloned beyond three generations were born with abnormalities, or wouldn’t survive birth. Scientists pointed to faulty histones in cloned embryos as the cause of these abnormalities. Histones are proteins in cell nuclei that package sequences of DNA into nucleosomes, a structural unit of the building-block molecules.
“So far, nobody has been able to explain the reason for this,” Teruhiko Wakayama of the RIKEN Center told New Scientist. “We thought that this limitation was caused by the accumulation of genetic or epigenetic abnormalities.”
But Wakayama’s group of researchers found a chemical that can overcome this issue. After inserting a nucleus from a cell from the mouse to be cloned into another mouse’s egg cell, the resulting hybrid cell is then bathed in trichostatin, an enzyme blocker. Trichostatin more faithfully resets the cell nucleus to an embryonic state, tricking the nucleus into acting like an embryonic cell.
“This is very impressive work. If this translates to other mammalian species - including humans - it could be a major game changer,” said Robert Lanza, chief medical officer at Advanced Cell Technology, a Massachusetts company that develops treatments using stem cells.
Cloning is a complicated game, and Wakayama is sticking to what he knows: “I am a mouse researcher and have no experience with other species. I will not even attempt to use rats, because male rats are extremely difficult to clone.”
This has applications beyond just scientific research. Cloning multiple generations from a single individual would be great for encouraging certain traits.
“If a ‘super cow’ that could produce a lot of milk or Kobe beef could be cloned at low cost, then not only consumers but also farmers would be happy,” said Wakayama.
The researchers are also looking into cloning mice from other, less desirable sources. Wakayama’s team is now planning to an attempt to clone individuals from stuffed bodies, excrement and mouse fur. If it succeeds in mice, this could be a possible method for cloning extinct animals from preserved remains or museum specimens.
