By Rebecca Morelle
BBC News science reporter
Snuppy, the cloned dog created by disgraced South Korean scientist Hwang Woo-suk, has been formally confirmed as an authentic genetic copy.
Nature commissioned an independent analysis of Snuppy
The journal Nature has released details of an independent analysis showing the Afghan hound is a genuine clone.
The check was ordered following allegations that Hwang's landmark studies on human cloning were faked.
The fall-out from the case means future, high-profile scientific claims will be subjected to greater scrutiny.
Journals are likely to ask for more supporting data on papers which purport to be major breakthroughs; and in some cases, scientists may even open up their work to independent experimental analysis before they submit a paper for publication.
Fraud is rare
Peer review is the process scientific journals use to assess research before it is published; but it is not fail-safe.
Peer review is supposed to ensure that any study's methodology is sound, and that interpretation of data does not go beyond what can be reasonably justified.
Journals ask other "experts in the field" to undertake the review but it does not involve these referees either repeating experiments or testing samples resulting from a research project.
In effect, this means that those wishing to "cheat" the system by submitting fake research data can potentially do so.
And although cases of scientific fraud are incredibly rare, when misconduct occurs it can leave the scientific world reeling, as Hwang has shown.
As the journal which originally published details of Snuppy's arrival, Nature sought new tests on the animal to confirm no duplicity had occurred.
The checks were carried out by scientists at the National Human Genome Research Institute at the US-based National Institutes of Health.
"We received blood samples from the donor dog Tai, the clone Snuppy and the surrogate mother who is a Labrador retriever," explained canine geneticist Dr Elaine Ostrander
"We prepared DNA from those samples and then we tested them in two ways."
The team looked at DNA in the cell nucleus and in mitochondria, components of the cell's outer structures.
Samples were taken from Snuppy, the donor and the surrogate mother
They found that only Snuppy's nuclear DNA matched with the donor dog, as expected.
Snuppy's mitochondrial DNA did not match with the donor dog; this genetic material does not come from the animal being copied, but from the egg into which donor DNA is inserted.
"The data really supports the notion that Snuppy is a clone of Tai, and that Snuppy was developed using the technical approaches that the authors suggested in their paper," said Dr Ostrander.
'Integrity and trust'
But should this sort of independent testing be carried out before cloning research is published in a journal?
In a recent editorial, Nature weighed up the suggestion of carrying out such tests, but said: "Imposing such a standard on the cloning field as a condition of publication would be an overreaction, and one with a myriad of logistical problems".
Dr Ritu Dhand, chief biological sciences editor of Nature, told the BBC News website that imposing such a measure would also negate the values on which scientific endeavour is built.
"The whole point of scientific research is that it is based on integrity and trust," she said. "The reason that science is able to work this way is because a scientist's personal integrity counts for an enormous amount."
However, she did point out that research journals might now ask authors to submit data about mitochondrial DNA from donor and clone, as well as nuclear DNA.
"This is a positive and a negative control, and we can ask for both. And as a research journal, I think that that is a path we can follow," said Dr Dhand.
"But what we are not going to do is to say 'we don't believe you have sequenced the DNA that you say you have sequenced' - you have to take the scientists at trust at that level."
However, the Nature editorial did encourage scientists to seek independent verification for any landmark cloning studies, and to submit these to the journal.
In addition, it said that scientists should store samples of clone experiments for later possible verification if required.
Meanwhile, Science, the journal that published and then retracted Hwang's human cloning research, is undergoing its own internal investigation of the peer review process undertaken.
"We are doing a systematic review of the editorial history of both papers and our procedures for evaluating them, to search for ways in which we might improve those," Science's editor-in-chief Dr Donald Kennedy said in a statement when the journal retracted the research.
"[Outside experts] and we will be considering options for providing additional procedural safeguards."
Dr Kennedy said this could include requiring authors to detail their specific contributions to the research submitted, and to sign statements of concurrence with the conclusions of the research.
The recently formed Hinxton Group, an international consortium on stem cells, ethics and law, met last month to discuss how researchers can establish an international ethical framework for their work.
Both Dr Andrew Sugden, international managing editor of Science, and Philip Campbell, editor-in-chief of Nature, were present at the meeting and are members of the group.
One of the recommendations made by the group was for journal editors to ask authors of stem cell research papers to submit data verifying the authenticity of the stem cell line, and an explanation of how they had complied with accepted standards of good cell culture practice.
They also urged journal editors to require that the source of cells used in the research be clearly specified.
Whatever new methods journals decide to undertake for scientists submitting cloning research, the Nature editorial made it clear that any decisions needed to be clearly thought through.
"In the aftermath of this deception, we should all undertake close scrutiny of our procedures and standards, with an eye towards preventing it from ever happening again," it said.
But it also stressed that the scientific community should be vigilant against knee-jerk reactions and witch hunts.