Archive for the ‘cloning’ Category

by Lisa Winter

Over 200 million people are infected by malaria each year, and the majority of the 627,000 deaths per year are children younger than five. The disease is carried by mosquitos who act as vectors for the parasite. It’s only transmitted to humans by female mosquitoes, as they’re the only ones who bite. A team of researchers led by Andrea Crisanti of the Imperial College London managed to genetically modify mosquitos to produce 95% male offspring, eliminating mosquito populations along with the risk of malaria. The results of the study were published in Nature Communications.

In most species of mosquito, the females need a blood meal in order to acquire the nutrients to create viable eggs. When she does, she can lay about 200 eggs at a time in water, and up to 3,000 eggs over the course of her lifetime. About half of those offspring will be daughters, many of whom will live long enough to produce that amount of offspring also. For humans living near mosquitos carrying the parasite that causes malaria, those numbers of female mosquitos present a very real threat.

But what if the numbers could be skewed so that the sex ratio favors males, who are harmless to humans? This is exactly what Crisanti’s team set out to do with Anopheles gambiae, a species of mosquito endemic to sub-Saharan Africa, where 95% of malaria deaths occur. The researchers modified the males with the enzyme I-Ppol, which excises the X chromosome during spermatogenesis. This renders sperm that would produce daughters to be non-functional, while the sperm that will create male offspring are unaffected. As a result, about 95% of the resulting offspring are male.

Next, modified males were introduced to five caged wild-type populations. As the males mated with the females, they passed along the same mutation until it dominated the population. For four of the five populations, it took only six generations for the mosquitos to die out due to a lack of females.

“What is most promising about our results is that they are self-sustaining,” co-author Nikolai Windbichler said in a press release. “Once modified mosquitoes are introduced, males will start to produce mainly sons, and their sons will do the same, so essentially the mosquitoes carry out the work for us.”

This study was the first to successfully manipulate mosquito sex ratios, and it was done in a big way. The researchers hope that this information will be used to develop genetic mutations to be used in the wild, bringing large populations of mosquitos to their knees.

“The research is still in its early days, but I am really hopeful that this new approach could ultimately lead to a cheap and effective way to eliminate malaria from entire regions,” added lead author Roberto Galizi. “Our goal is to enable people to live freely without the threat of this deadly disease.”

Of course, while eradicating the mosquitos would be fantastic for eliminating the threat of malaria, what other affects would it have? Wouldn’t there be harsh consequences for the ecosystem? After all, mosquitos have been on the planet for about 100 million years and represent 3,500 species. As it turns out, mosquitos wouldn’t really be missed if they were to disappear (http://www.nature.com/news/2010/100721/pdf/466432a.pdf). While mosquitos can act as pollinators as well as a food source for other animals, their absence would be merely a temporary setback before another species filled the niche. Of course, there is a gamble in assuming the replacement organism would be harmless.

“Malaria is debilitating and often fatal and we need to find new ways of tackling it. We think our innovative approach is a huge step forward. For the very first time, we have been able to inhibit the production of female offspring in the laboratory and this provides a new means to eliminate the disease,” Crisanti explained.

Each year, sub-Saharan Africa loses about $12 billion in economic productivity due to malarial infections. Considering developed areas in these countries have per capita incomes of about US$1500, this would have very real implications for the quality of life for people in those areas. Eliminating that disease would also allow doctors and hospitals to address other health concerns, and the environment would likely benefit from not having to use insecticides.

http://www.iflscience.com/health-and-medicine/gm-mosquitos-could-eradicate-wild-populations-only-producing-male-offspring

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Scientists from South Korea have devised a technique for cloning adult stem cells that doesn’t involve the destruction of human embryos. The resulting stem cells, which are highly personalized, could be used to treat illnesses such as heart disease and blindness — but the technique could also be used to clone adults.

It’s a process called therapeutic cloning and it involves the production of embryonic cells that are genetically identical to those of the donor, typically for the purpose of using the resulting pluripotent cells to treat disease. The scientists, whose study now appears in Cell, extracted skin cells from two adult males, aged 35 and 75. The DNA was then fused with human eggs donated by four adult women.

A burst of electricity was used to fuse grown cells with eggs whose own DNA had been removed. The eggs then multiplied and soon developed into embryos in the shape of a hollow sphere. This resulted in pluripotent cells — cells that can turn into any kind of human cell.

Last year, scientists essentially did the same thing, though the cells were derived from human fetal and infant DNA (which tend to be more malleable). This technique is considered much more ethically palatable because it does not involve the destruction of human embryos.

As noted, and in addition to creating personalized stem cells to treat such conditions as Parkinson’s disease, heart disease, multiple sclerosis or type-1 diabetes, the technique could be used to clone human adults.

http://io9.com/researchers-clone-stem-cells-from-human-adults-1564755314

Thanks to Da Brayn for bringing this to the attention of the It’s Interesting community.

A team of international scientists are extracting high quality DNA from the remains of a woolly mammoth that lived 43,000 years ago, with the aim of joining it with the DNA of an elephant, they told The Siberian Times Thursday. Results from the necropsy of the woolly mammoth in Yakutsk, Sakha Republic — due to wind up Saturday after more than 10 months of analysis — has caused “palpable excitement” within the team of scientists, hailing from Russia, the UK, the United States, Denmark, South Korea, and Moldova.

“The data we are about to receive will give us a high chance to clone the mammoth,” Radik Khayrullin, vice president of the Russian Association of Medical Anthropologists, told The Siberian Times in Yakutsk. He urged responsibility in any attempts to clone the woolly mammoth. “It is one thing to clone it for scientific purpose, and another to clone for the sake of curiosity,” he said. Geneticists are reportedly searching for an Asian elephant whose egg could be injected with cloned material from the woolly mammoth. That same or another female elephant would be the surrogate mother of the resulting fertilzed egg. Any resulting wooly mammoth/elephant hybrid baby would have to be female, since there is no y-chromosome material from the wooly mammoth, who was a female. At any rate, such a procedure would take decades to perfect, experts said.

Semyon Grigoriev, head of the Museum of Mammoths of the Institute of Applied Ecology of the North at the North Eastern Federal University, told The Siberian Times that because the evolutionary paths of the mammoth and the elephant diverged so long ago, cloning will be challenging. However, the samples will allow geneticists to completely decode the DNA of the mammoth.

The Russian woolly mammoth was between 50 and 60 years old when she died. Though the upper part of her carcass has been devoured by animals, the lower part (the legs and a detached trunk) was “astonishingly, very well preserved,” Viktoria Egorova, chief of the research and clinical diagnostic laboratory of the medical clinic of North-Eastern Federal University told The Siberian Times. The mammoth, which may have met her demise by falling through a hole in the ice, lay in the permafrost of Maly Lyakhovskiy Island until it was found last May.
The mammoth as a species disappeared from Siberia at the end of the Pleistocene era about 10,000 years ago, with warming climate and hunting by humans thought to be contributing factors. An isolated population of woolly mammoths persisted on Wrangel Island in the Arctic Ocean, between the Chukchi and East Siberian Seas, until around 4,000 years ago.

‘We have dissected the soft tissues of the mammoth, and I must say that we didn’t expect such results,” Dr. Egorova told The Siberian Times. The necropsy revealed well-preserved muscle and adipose tissues (loose connective tissues which store fat), and “blood vessels with strong walls,” and within intact blood vessels themselves, for the first time ever in an ancient carcass of an extinct animal, erythrocytes, or red blood cells that contain the oxygen-carrying molecule hemoglobin, Egorova told The Siberian Times.

Biologists have been able to discern cells within the woolly mammoth’s blood that had been in the process of migration (involved in growth and healing) within the lymphoid tissue when the woolly mammoth died, a finding Egorova termed “another great discovery.” The intestines contained remains of the vegetation eaten by the mammoth; its multi-chambered stomach was preserved, as was a kidney, which contained fragments Egorova suspects are kidney stones.

One of the Canadian scientists looking foward to anayzing blood samples from the woolly mammoth is Kevin Campbell, a University of Manitoba professor of environmental and evolutionary physiology who has rearched and written on the subject of hemoglobin in woolly mammoths. In 2010, Campbell wrote a letter in the journal Nature Genetics describing how he had genetically resurrected and analyzed woolly mammoth hemoglobin “to reveal for the first time…the structural underpinnings of a key adaptive physiochemical trait in an extinct species.” He discovered that whereas the efficiency of hemoglobin in elephants to offload oxygen to respiring cells is hampered at low temperatures, mammoth hemoglobin has amino acid substitutions that “provide a unique solution to this problem and thereby minimize energetically costly heat loss.” Since then, Campbell has recreated the hemoglobin of woolly mammoths.

Campbell, who described himself as “bitterly disappointed” that he couldn’t make the necropsy of the woolly mammoth in Russia, said he would be doing the next best thing next week; joining one of his collaborators, Roy E. Weber at Aarhus University, Denmark who will be returning from Russia with some muscle and blood samples extracted from the woolly mammoth. If nothing else, the blood samples may allow Campbell to verify the presence of cold-tolerant hemoglobin in woolly mammoths. “It’s one thing to synthesize mammoth hemoglobin in bacteria: It’s quite another story to study the real thing from a 43,000 year-old specimen,” Campbell told the International Science Times. “No other specimen has ever been so well preserved that we could potentially obtain hemoglobin oxygen-binding data from it. This specimen offers the unique opportunity to collect precisely the same kind of physiologically relevant information from an extinct species as I could from those that are still alive.”

Climate change (as destructive a force as it is for the planet) has proven to be a boon for evolutionary physiologists interested in examining extinct animals. “One of the dirty little secrets of this field is that the increased melting of the North affords the finding of many, many more specimens,” Campbell said. “I don’t want to encourage further global warming, but it is a benefit from permafrost melting and so much being exposed, that they are finding woolly rhinos, bison, a crazy number of ancient horses and specimens in the Canadian and Russian Arctic.” Gold mining and industrial development has also unearthed more prehistoric animals than ever before in human history.

The researchers who peformed the autopsy on the woolly mammoth will hold a conference in Greece in May to announce the results.

http://www.isciencetimes.com/articles/6946/20140313/woolly-mammoth-dna-cloning-elephant-clone.htm

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By David Shukman

You hear the squeals of the pigs long before reaching a set of long buildings set in rolling hills in southern China.

Feeding time produces a frenzy as the animals strain against the railings around their pens. But this is no ordinary farm.

Run by a fast-growing company called BGI, this facility has become the world’s largest centre for the cloning of pigs.

The technology involved is not particularly novel – but what is new is the application of mass production.

The first shed contains 90 animals in two long rows. They look perfectly normal, as one would expect, but each of them is carrying cloned embryos. Many are clones themselves.

This place produces an astonishing 500 cloned pigs a year: China is exploiting science on an industrial scale.

To my surprise, we’re taken to see how the work is done. A room next to the pens serves as a surgery and a sow is under anaesthetic, lying on her back on an operating table. An oxygen mask is fitted over her snout and she’s breathing steadily. Blue plastic bags cover her trotters.

Two technicians have inserted a fibre-optic probe to locate the sow’s uterus. A third retrieves a small test-tube from a fridge: these are the blastocysts, early stage embryos prepared in a lab. In a moment, they will be implanted.

The room is not air-conditioned; nor is it particularly clean. Flies buzz around the pig’s head.

My first thought is that the operation is being conducted with an air of total routine. Even the presence of a foreign television crew seems to make little difference. The animal is comfortable but there’s no sensitivity about how we might react, let alone what animal rights campaigners might make of it all.

I check the figures: the team can do two implantations a day. The success rate is about 70-80%.

Dusk is falling as we’re shown into another shed where new-born piglets are lying close to their mothers to suckle. Heat lamps keep the room warm. Some of the animals are clones of clones. Most have been genetically modified.

The point of the work is to use pigs to test out new medicines. Because they are so similar genetically to humans, pigs can serve as useful “models”. So modifying their genes to give them traits can aid that process.

One batch of particularly small pigs has had a growth gene removed – they stopped growing at the age of one. Others have had their DNA tinkered with to try to make them more susceptible to Alzheimer’s.

Back at the company headquarters, a line of technicians is hunched over microscopes. This is a BGI innovation: replacing expensive machines with people. It’s called “handmade cloning” and is designed to make everything quicker and easier.

The scientist in charge, Dr Yutao Du, explains the technique in a way that leaves me reeling.

“We can do cloning on a very large scale,” she tells me, “30-50 people together doing cloning so that we can make a cloning factory here.”

A cloning factory – an incredible notion borrowed straight from science fiction. But here in Shenzhen, in what was an old shoe factory, this rising power is creating a new industry.

The scale of ambition is staggering. BGI is not only the world’s largest centre for cloning pigs – it’s also the world’s largest centre for gene sequencing.

In neighbouring buildings, there are rows of gene sequencers – machines the size of fridges operating 24 hours a day crunching through the codes for life.

To illustrate the scale of this operation, Europe’s largest gene sequencing centre is the Wellcome Trust Sanger Institute near Cambridge. It has 30 machines. BGI has 156 and has even bought an American company that makes them.

BGI’s chief executive, Wang Jun, tells me how they need the technology to develop ever faster and cheaper ways of reading genes.

Again, a comparison for scale: a recently-launched UK project seeks to sequence 10,000 human genomes. BGI has ambitions to sequence the genomes of a million people, a million animals and a million plants.

Wang Jun is keen to stress that all this work must be relevant to ordinary people through better healthcare or tastier food. The BGI canteen is used as a testbed for some of the products from the labs: everything from grouper twice the normal size, to pigs, to yoghurt.

I ask Wang Jun how he chooses what to sequence. After the shock of hearing the phrase “cloning factory”, out comes another bombshell:

“If it tastes good you should sequence it,” he tells me. “You should know what’s in the genes of that species.”

Species that taste good is one criterion. Another he cites is that of industrial use – raising yields, for example, or benefits for healthcare.

“A third category is if it looks cute – anything that looks cute: panda, polar bear, penguin, you should really sequence it – it’s like digitalising all the wonderful species,” he explains.

I wonder how he feels about acquiring such power to take control of nature but he immediately contradicts me.

“No, we’re following Nature – there are lots of people dying from hunger and protein supply so we have to think about ways of dealing with that, for example exploring the potential of rice as a species,” the BGI chief counters.

China is on a trajectory that will see it emerging as a giant of science: it has a robotic rover on the Moon, it holds the honour of having the world’s fastest supercomputer and BGI offers a glimpse of what industrial scale could bring to the future of biology.

Read more: http://www.bbc.co.uk/news/science-environment-25576718

Thanks to Kebmodee for bringing this to the attenion of the It’s Interesting community.