People with milk allergies often turn to products like rice and soy milks. But now, in a twist, there is a new source of hypoallergenic milk in the offing: genetically-modified cows.
The Internet has been burning up with an ice age storyline over the past few days: Researchers in Japan led by Akira Iritani announced their plan to clone a woolly mammoth within four to six years, recreating a colossal beast not seen on Earth in thousands of years. But as enthusiastic as DISCOVER is for cloned mammoths (and believe us, we’re psyched), the project is still a long way from success.
First, the backstory.
Researchers from Kinki University’s Graduate School of Biology-Oriented Science and Technology began the study in 1997. On three occasions, the team obtained mammoth skin and muscle tissue excavated in good condition from the permafrost in Siberia. However, most nuclei in the cells were damaged by ice crystals and were unusable. The plan to clone a mammoth was abandoned. [Daily Yamiuri]
That initial effort was a DISCOVER cover story back in 1999. Now, though, the dream is back, thanks to newly developed methods to get around that icy problem.
The team, which has invited a Russian mammoth researcher and two US elephant experts to join the project, has established a technique to extract DNA from frozen cells, previously an obstacle to cloning attempts because of the damage cells sustained in the freezing process. Another Japanese researcher, Teruhiko Wakayama of the Riken Centre for Developmental Biology, succeeded in 2008 in cloning a mouse from the cells of another that had been kept in temperatures similar to frozen ground for 16 years. [AFP]
Last year DISCOVER asked the question, “Did We Mate With Neanderthals, or Did We Murder Them?” Now, Zach Zorich at Archaeology magazine is asking another big question about our hominid siblings: Should we bring them back?
Thanks to a slew of recent advances, the possibility is getting closer. 80beats reported a year ago that researchers had published the rough draft of the Neanderthal genome. However, that’s likely to contain many errors because it’s so difficult to reconstruct ancient DNA. Within hours of death, cells begin to break down in a process called apoptosis. The dying cells release enzymes that chop up DNA into tiny pieces. In a human cell, this means that the entire three-billion-base-pair genome is reduced to fragments about 50 base-pairs long [Archaeology].
Even if scientists succeed in figuring out the entire Neanderthal genome, they’d be faced with another problem before they could even consider the possibility of cloning one of these ancient hominids: We don’t have any living Neanderthal cells to work with. Thus, researchers will have to figure out how to put DNA into chromosomes, and how to get those chromosomes into the nucleus of a cell. What about altering the DNA inside a living human cell, and tweaking our genetic code to match the Neanderthal’s? This kind of genetic engineering can already be done, but very few changes can be made at one time. To clone a Neanderthal, thousands or possibly millions of changes would have to be made to a human cell’s DNA [Archaeology].
Even if scientists manage to put Neanderthal DNA in a cell nucleus, their problems aren’t over. The next step in creating a baby clone is to move the cell nucleus into the egg of a related species in a technique called nuclear transfer, and then implanting the altered egg in a female who can bear it to term. But in this process, which has been extensively tested on animals, cells often get sick or die, causing fetuses to die in the womb or clones to die young. That’s why the vast majority of scientists oppose using this method on people. Even if nuclear transfer cloning could be perfected in humans or Neanderthals, it would likely require a horrifying period of trial and error [Archaeology].
The disgraced South Korean researcher whose breakthrough cloning research was exposed as a fraud in 2005 now faces up to four years in prison. Prosecutors asked for the four-year sentence in court today, where the researcher, Hwang Woo-suk, is standing trial for fraud, misusing $2.25 million in state funds, and violating bioethics laws by illegally buying human eggs for his research. “The people’s disappointment was very serious because their expectation for his stem cell research had been high,” an unidentified prosecutor told the courtroom. He said Hwang tarnished South Korea’s image abroad…. Hwang pleaded for leniency, saying if the court forgives him he is ready to “pour the last of my passion” into research [AP].
Hwang became a national hero to South Korea in 2004, when he claimed to have cloned human embryonic stem cells, a feat that was thought to be impossible because of the complexities of human cells. Embryonic stem cells are of great interest to medical researchers because they can develop into any kind of adult cell, and could theoretically be used to replace malfunctioning cells that cause disease. A year later, Hwang said the team created human embryonic stem cells genetically matched to specific patients — a purported breakthrough that promised a way to withstand rejection by a patient’s immune system [AP].
After years of fiddling with human, mouse, rabbit, and cow cells, researcher Robert Lanza has declared that it’s impossible to create human-animal hybrid embryos, but that human cloning appears to be eminently doable.
Lanza wasn’t trying to create some freakish chimera, nor did he intend to bring forth a squalling baby as the world’s first human clone. But ever since researchers cloned Dolly the sheep in 1996 by transferring the nucleus of one of her cells into the nucleus-free egg of another sheep, scientists, ethicists, politicians, and the public have wondered whether a person could be cloned in the same way [ScienceNOW Daily News]. While human cloning has largely been rejected as unethical, many researchers are excited by the idea of “therapeutic” cloning, in which the same technique could be used to create embryos that would be harvested for medically useful stem cells. Those stem cells would have the same genetic profile as a patient and would thus avoid immune-rejection issues [ScienceNOW Daily News].
Because of the shortage of human egg donors, the hybrids were proposed as a way of creating large numbers of human embryo clones to harvest stem cells in bulk [Telegraph]. Lanza’s stem cell company, Advanced Cell Technology, has spent several years inserting human nuclei into egg cells from mice, rabbits, and cows, but all of the thousands of embryos they created in this way failed to develop. “At first we thought it would just be a matter of tweaking the culture conditions,” says Lanza. But “the problem was far more fundamental” [Nature News].
An extinct mountain goat that was once common in the Pyrenees briefly became the first animal to be brought back from extinction, as researchers used frozen DNA to produce a clone. But the newborn kid died within minutes of birth due to breathing difficulties, signaling that the Jurassic Park dream of resurrecting extinct species is still some way off.
The Pyrenean ibex, or bucardo, is a subspecies of the Spanish ibex that is believed to have died out completely in 2000. Before the death of the last known individual (a 13-year-old female known as Celia), biologists captured her and took cells from her skin and ears, which were frozen in liquid nitrogen. An earlier cloning attempt using the skin cells failed during gestation. But the latest attempt involved the creation of 439 ibex-goat hybrid cloned embryos made by inserting the cell nuclei of the ibex’s skin cells into the egg cells of domestic goats which had their own cell nuclei removed. Of these cloned embryos, 57 were transferred into surrogate mothers and seven resulted in pregnancies, but only one goat gave birth and the newborn clone died after seven minutes as a result of lung deformities [The Independent].
A Florida couple has just received a genetic copy of their beloved and deceased golden Labrador Sir Lancelot, naming the three-month-old puppy Lancelot Encore. The couple paid $155,000 for one of the first commercially cloned dogs in the world, and say the money was well spent. “He was a wonderful dog,” said Nina Otto, 66. “Money wasn’t an object. We just wanted our wonderful, loving dog back” [ABC News]. The project was masterminded by the California biotech company BioArts.
Lancelot Encore joins a handful of other dogs cloned either commercially or as a proof of concept, and the latest success seems to indicate that researchers have thoroughly overcome the scientific barriers to cloning man’s best friend. Canines are considered one of the more difficult mammals to clone because of their reproductive cycle that includes difficult-to-predict ovulations [Reuters]. Now the fate of the fledging pet cloning industry is largely dependent on whether dog lovers think that clones are worth the high price tag. However, just yesterday another cloning company announced a new technique that could reduce the cost of dog cloning to about $50,000 within three years.
The Tasmanian tiger may have been threatened by inbreeding before humans hunted the marsupial into extinction, a new genetic analysis suggests. The last captive tiger died at a Tasmanian zoo in 1936 after a decades-long effort by farmers and hunters to kill the creatures and collect a government bounty, but the new study suggests that the tigers’ lack of genetic diversity left them particularly vulnerable to the human onslaught and outbreaks of disease. “It’s looking like the thylacines were sort of on their last legs,” says Webb Miller [Science News], one of the coauthors.
Researchers sequenced the mitochondrial DNA of two Tasmanian tigers, more properly known as thylacines, from tissue samples preserved at museums in Sweden and the United States. And while the researchers’ main goal was to investigate the roots of the thylacine’s extinction, they acknowledge that having a complete genome at their disposal is sure to prompt talk of cloning. Says Miller: “Our goal is to learn how to prevent endangered species from going extinct…. I want to learn as much as I can about why large mammals become extinct because all my friends are large mammals,” Professor Miller added. “However, I am expecting that publication of this paper also will reinvigorate discussions about possibly bringing the extinct Tasmanian tiger back to life” [BBC News]. Some scientists think that the thylacine would be one of the easiest extinct animals to resurrect, as it died out recently and several well-preserved specimens exist in museums.
The Vatican has issued new ethical guidelines in response to the biomedical advances of the last 20 years, and has come down hard on assisted reproduction technologies and genetic engineering. The document, Dignitas Personae (which translates as “human dignity”), reaffirm the church’s opposition to in vitro fertilization. It also tells Catholics that the church also doesn’t condone “adopting” leftover fertilized embryos from fertility clinics, and frowns upon the genetic testing of embryos before implantation, which could lead to the embryo being discarded. The Vatican says these techniques violate the principles that every human life — even an embryo — is sacred, and that babies should be conceived only through intercourse by a married couple [The New York Times].
These instructions stem from two fundamental theological principles: that life begins at conception and that the origin of human life is the “fruit of marriage.” … The document now makes clear that the morning-after pill, RU-486, and intrauterine devices (IUDs), which either intercept the embryo before implantation or eliminate it after implantation, “fall within the sin of abortion” [Scientific American]. The guidelines may come as a surprise to many Catholics who don’t realize that the church takes such a strict stance on medical technologies like in vitro fertilization that are often seen as routine and beneficial.
In a big step forward for cloning research, scientists have produced healthy clones of mice that were dead and frozen for 16 years. Researchers say the new technique could allow conservationists to freeze tissue from endangered species, which could then be used to produce clones if those species become extinct. The finding also raises hopes of one day being able to resurrect extinct animals frozen in permafrost, such as the woolly mammoth, says [lead researcher] Teruhiko Wakayama…. “It would be very difficult, but our work suggests that it is no longer science fiction,” he says [New Scientist].
Researchers have previously produced clones from frozen animal tissue, but only from specimens that were preserved with special chemicals to protect cells from damage during the deep freeze. In this study, published in the Proceedings of the National Academy of Sciences [subscription required], no such special precautions were taken when the mice were stowed in a freezer 16 years ago. Many zoos are not in a position to collect cells and freeze them in such a way as to preserve their viability, says [cloning expert] Robert Lanza … but they can put a dead animal “in a plastic bag and throw it in the freezer”, he adds. “With a kitchen freezer you could store the genetic diversity of every panda in existence” [New Scientist].