By Guest Nicole
SUPPORTERS of vaping claim it is a way for smokers to quit and it is also a “lesser evil” than conventional cigarettes.
But new research suggests vaping increases the level of DNA-damaging compounds. If cells cannot repair DNA damage the risk of cancer can increase, say scientists.
The study analysed the saliva and mouth cells of five e-cigarette users before and after a 15-minute vaping session. Researchers found increased levels of toxic chemicals formaldehyde, acrolein and methylglyoxal
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A Chinese researcher claimed to have helped make the world's first genetically edited babies, and the scientific community responded with shock and alarm.
By Guest Nicole
Experts welcome news of successful mitochondrial transfer but caution against operating in countries beyond regulations
Dr John Zhang with the world’s first baby born using DNA from three people. The baby is reported to be healthy. Photograph: New Hope Fertility Center
The world’s first baby to be born from a new procedure that combines the DNA of three people appears to be healthy, according to doctors in the US who oversaw the treatment.
The baby was born on 6 April after his Jordanian parents travelled to Mexico where they were cared for by US fertility specialists.
Doctors led by John Zhang, from the New Hope Fertility Center in New York, decided to attempt the controversial procedure of mitochondrial transfer in the hope that it would give the couple a healthy child.
While many experts welcomed news of the birth, some raised concerns that the doctors had left the US to perform the procedure beyond the reach of any regulatory framework and without publishing details of the treatment.
Speaking to the New Scientist, Zhang said he went to Mexico where “there are no rules” and insisted that doing so was right. “To save lives is the ethical thing to do,” he said.
Mitochondrial transfer was legalised in the UK in 2015 but so far no other country has introduced laws to permit the technique. The treatment is aimed at parents who have a high risk of passing on debilitating and even fatal genetic diseases to their children.
The mitochondrial transfer technique is aimed at those with a high risk of passing on debilitating diseases. Photograph: Ben Birchall/PA
The boy’s mother carries genes for the fatal Leigh syndrome, which harms the developing nervous system. The faults affect the DNA in mitochondria, the tiny battery-like structures that provide cells with energy, and are passed down from mother to child.
Ten years after the couple married, the wife became pregnant but she lost the baby in the first of four miscarriages. The couple had a baby girl in 2005 who died at the age of six, and later, a second child who lived for only eight months. Tests on the wife showed that while she was healthy, about one-quarter of her mitochondria carried the genes for Leigh syndrome.
When the couple approached Zhang for help, he decided to try the mitochondrial transfer procedure. He took the nucleus from one of the woman’s eggs and inserted it into a healthy donor’s egg that had had its own nucleus removed. He then fertilised the egg with the husband’s sperm.
The US team created five embryos but only one developed normally. This was implanted into the mother and the baby was born nine months later.
The baby is not the first child to be born with DNA from three people. In the 1990s, fertility doctors tried to boost the quality of women’s eggs by injecting cytoplasm, the cellular material that contains mitochondria, from healthy donor eggs. The procedure led to several babies being born with DNA from the parents plus the healthy donor. Some of the children developed genetic disorders and the procedure was banned.
Speaking about the latest case, Dusko Ilic, a stem cell scientist at King’s College London, said: “Without much ado, it appears the first mitochondrial donation baby was born three months ago. This was an ice-breaker. The baby is reportedly healthy. Hopefully, this will tame the more zealous critics, accelerate the field, and we will witness soon the birth of the first mitochondrial donation baby in the UK.”
But some questions remained, he said. “By performing the treatment in Mexico, the team were not subject to the same stringent regulation as some other countries would insist on. We have no way of knowing how skilful or prepared they were, and this may have been a risky thing to do.
“On the other hand, we have what appears to be a healthy baby. Because it was successful, fewer questions will be raised, but it is important that we still ask them.
“Was this the first time ever they performed the technique or were there other attempts and they are reporting this one because it was successful?
“This and other important questions remain unanswered because this work has not been published and the rest of the scientific community has been unable to examine it in detail. It’s vital that that happens soon.”
Alison Murdoch, a fertility doctor at Newcastle University, said: “If this baby has been born as suggested then that would be great news. The translation of mitochondrial donation to a clinical procedure is not a race but a goal to be achieved with caution to ensure both safety and reproducibility.”
Details of the birth are due to be presented at the American Society for Reproductive Medicine meeting in Salt Lake City in October.
Doug Turnbull, a neurology professor at Newcastle University who pioneered mitochondrial transfer in the UK, said the technique offered hope to mothers who carried mitochondrial DNA mutations.
“There have been extensive discussions in the UK to ensure that families with mitochondrial disease get the best possible advice about their reproductive options and that any new IVF-based technique is appropriately regulated and funded. This abstract gives very little information about the technique used, the follow up of the child or the ethical approval process.”
This article was amended on 27 September 2016 to remove the names of some of the parties involved, because information changed about whether permission to name had been given.
By Guest Nicole
What could be more alien than a virus? It’s a nanobiological weapon — a microscopic protein shell holding a few genes that hijack a cell’s internal machinery, forcing it to make new viruses. The battles we fight with these alien enemies brings malaise, scars and even death.
Yet as foreign as viruses may seem, the boundary between us and them is turning out to be remarkably blurry. We use DNA from viruses to do things that are essential to our own survival, scientists are finding. Somehow, we have managed to domesticate some of these invaders.
A number of viruses replicate by inserting their DNA into our own genes. On rare occasions, their genes get passed down to future generations.
At first, the newly acquired genes behave a lot like regular virus genes. They can still coax host cells to make full-fledged viruses that can escape and infect other victims.
But over the generations, they lose the ability to escape human cells. They can still make copies of themselves, but those copies get incorporated into the host cell’s DNA. Over time these so-called endogenous retroviruses lose even the ability to replicate, becoming harmless fragments adrift in the human genome.
Endogenous retroviruses first invaded the cells of our primate ancestors more than 50 million years ago. Scientists have identified over 100,000 of these fragments in the human genome, accounting for 8 percent of our DNA.
Some of these fragments have become part of our biology and perform tasks that benefit us. “A host essentially takes over a viral gene and puts it to work for its own ends,” said Aris Katzourakis, an evolutionary biologist at the University of Oxford.
Human cells may have even co-opted viral DNA for a particularly ironic purpose: to fight other viruses.
Twenty years ago, British scientists investigated a virus-fighting protein called Fv1. It protects mice by latching onto invading viruses and preventing them from inserting their DNA into the genome of a mouse cell. The gene that encodes Fv1 came originally from a mouse-infecting virus, the researchers discovered.
Other proteins produced by viral DNA block the receptors through which newcomer viruses invade. Some viral proteins disrupt the replication of attacking viruses, leaving them unable to invade other cells.
On Thursday in the journal Science, scientists reported that human ancestors also harnessed viral DNA to rewire their own genetic circuitry.
Guillaume Bourque, a geneticist at McGill University who was not involved in the study, praised it for revealing a new way in which evolution harnessed viral DNA to strengthen the immune system. “In that sense, it’s a first,” he said.
To fight invading viruses, a cell needs to turn on many genes at once. The genetic switches that make this possible are stretches of DNA next to each gene, which are themselves activated by proteins.
From left, University of Utah geneticists Cedric Feschotte, Edward Chuong and Nels Elde. Their research suggests that viral DNA fragments in the human genome may help fight viral infections.
UNIVERSITY OF UTAH HEALTH SCIENCES
One such protein is interferon, which is produced when a cell is attacked by a virus. Interferon turns on genes that cells use to defend themselves.
Cedric Feschotte and his colleagues at the University of Utah wondered if our cells harnessed viral gene switches to turn on immune genes. They discovered many pieces of viral DNA sitting next to genes that belong to the interferon network.
The scientists edited the DNA of human cells they grew in a dish, chopping out some of the viral switches near interferon-responsive genes. Then they exposed those cells to interferon. The immunity genes, they found, barely woke up.
In another experiment, the team exposed the altered cells to viruses and found that the cells mounted only a weak defense. “They became more susceptible to infection,” Dr. Feschotte said.
The results suggest that many of the gene switches that help defend our cells from viruses actually came from viruses.
Dr. Feschotte noted that a number of viruses that infect humans today have gene switches that turn on their genes when they sense their host cells have launched an interferon defense. Such gene switches would have been easily captured by our own cells.
The new study adds even more evidence of the importance of viral DNA in our evolution. By spreading their DNA around our genome, viruses provided us with new switches that our cells could harness.
But understanding the full effect of viruses on our evolution will take years, according to Dr. Feschotte. “It’s the sort of thing that I think about night and day,” he said.
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