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Dec. 22, 2011 — The genetic changes underlying the evolution of new species are still poorly understood. Genetic studies in domestic animals can shed light on this process due to the rapid evolution they have undergone over the last 10,000 years. A new study describes how a complex genomic rearrangement causes a fascinating phenotype in chickens.
In the study published in PLoS Genetics researchers at Uppsala University, Swedish University of Agricultural Sciences, North Carolina State University and National Chung-Hsing University have investigated the genetic basis of fibromelanosis, a breed characteristic of the Chinese Silkie chicken (image on left). This trait involves a massive expansion of pigment cells that not only makes the skin and comb black but also causes black internal organs.
Chickens similar in appearance to the Silkie were described by Marco Polo when he visited China in the 13th century and Silkie chickens have a long history in Chinese cuisine and traditional Chinese medicine.
"We have shown that the genetic change causing fibromelanosis is a complex rearrangement that leads to increased expression of Endothelin 3, a gene which is known for promoting the growth of pigment cells," explains Ben Dorshorst the post-doctoral researcher responsible for the work.
The research group led by Leif Andersson has by now characterized a number of traits in domestic animals, and a clear trend is emerging, namely that genomic rearrangements have contributed significantly to the rapid evolution of domestic animals. Other examples include Greying with age in horses and mutations affecting the size and shape of the comb in chickens.
"We have good reason to believe that such rearrangements have also played a significant role in the evolution of other species, including ourselves," concludes Leif Andersson.
The researchers also studied other chicken breeds where fibromelanosis occurs, including the Bohuslän-Dals svarthöna breed (image on right) from Sweden, and they found that all fibromelanotic breeds carried the exact same very unusual mutation. This finding is consistent with anecdotal evidence suggesting that this Swedish breed of chicken inherited their black skin and internal connective tissue color from Asian chickens that were first brought to Norway by a sailor on the East Asian trade routes centuries ago. This is a nice example of how humans have distributed a single novel mutation with an interesting effect when they developed breeds of domestic animals around the world. -- It is obvious that humans have had a strong affection for biological diversity in their domestic animals, says Leif Andersson.
holy crap, Leif freaking Andersson! I actually know that guy. tall swedish looking dude (well, he is one). small world. he does companion animal genetics and I ran into him at a conference a few months ago. a friend of mine actually is doing her postdoc at Uppsala as well (not in his lab though). [Reply]
Early Canid Domestication: The Farm-Fox Experiment
Foxes bred for tamability in a 40-year experiment exhibit remarkable transformations that suggest an interplay between behavioral genetics and development Lyudmila Trut
At an experimental farm in Novosibirsk, Siberia, geneticists have been working for four decades to turn foxes into dogs. They are not trying to create the next pet craze. Instead, author Trut and her predecessors hope to explain why domesticated animals such as pigs, cattle and dogs are so different from their wild ancestors. Selective breeding alone cannot explain all the differences. Trut's mentor, the eminent Russian geneticist Dmitri Belyaev, thought that the answers lay in the process of domestication itself, which might have dramatically changed wolves' appearance and behavior even in the absence of selective breeding. To test his hypothesis, Belyaev and his successors at the Institute have been breeding another canine species, silver foxes, for a single trait: friendliness toward people. Although no one would mistake them for dogs, the Siberian foxes appear to be on the same overall evolutionary path—a route that other domesticated animals also may have followed while coming in from the wild.
Originally Posted by mike_b_284:
I believe the key to this will be found in epigentetics
uh, no. in this case, it's pleitropy. it's classic genetics--the behavior genes are in linkage disequilibrium with the genes that cause floppy ears and the coat color change.
epigenetics, however, may have some effect on other behavioral components, but it's still a rapidly changing field. [Reply]
There's little that I find more depressing or exasperating than coming home to see a huge pile of dirty dishes. Washing dishes is the worst. Really, that's why the dishwasher was invented. But loading and unloading dishwashers also can be something of a tedious chore. So we should all be thrilled that Tomorrow Machine, a Swedish design company, has invented this self-cleaning plate and bowl.
These are made entirely of cellulose — plant pulp — finished with a water-repellent coating found in nature on the leaves of lotus plants, nasturtiums, and elephant's-ear plants, and on the wings of some butterflies. These biological structures are water-repellent because they are roughened at a nano-scale level. This minimizes adhesion, causing droplets of water to bead rather than flatten. This means they easily roll off, taking dirt particles with them. For the lotus plant, this kind of coating keeps the plant's leaves free of dirt and contaminants, helping to ward off disease and parasites.
What does this mean for you? That cleaning this plate is as easy as tipping it over and watching the gunk roll off. No scrubbing necessary. Just like a lotus leaf:
The material is produced from a sheet of cellulose which is then pressed into a mold, making the cellulose harden like ceramic. The result is a plate lighter than ceramic, but which won't shatter when dropped.
The one big problem? The water-repellent coating is not yet approved for food consumption. That's a pretty big stumbling block, and only rigorous testing will tell whether hydrophobic coatings are safe to serve up food for human consumption. This means that it could be awhile before we see these plates used in homes and restaurants.
The plate was created for a project called Ekoportal 2035, commissioned by the Swedish Forest Industries Federation. They asked Tomorrow Machine and research institute Innventia to create three products that explore potential future uses for cellulose created from materials from Swedish forests.
Beside the self-cleaning plate and bowl, the project also produced a transparent digital touch screen made from nano-cellulose, and an item made from a cellulose-based plastic that can be 3D-printed. [Reply]
To cope with a growing shortage of hearts, livers, and lungs suitable for transplant, some scientists are genetically engineering pigs, while others are growing organs in the lab.
For Joseph Vacanti, the quest to build new organs began after watching the death of yet another child. In 1983, the young surgeon was put in charge of a liver transplantation program at Boston Children’s Hospital in Massachusetts. His first operation was a success, but other patients died without ever being touched by a scalpel. “In the mid-80s, kids who were waiting for organs had to wait for a child of the same size to die,” says Vacanti. “Many patients became sicker and sicker before my eyes, and I couldn’t provide them with what they needed. We had the team, the expertise, and the intensive care units. We knew how to do it. But we had to wait.”
On the other side of the Atlantic, David Cooper was having the same problem. Having taken part in the first successful series of heart transplants in the United Kingdom, he had moved to South Africa to run a transplantation program at the University of Cape Town Medical School. At the time, people had a 50/50 chance of surviving such a procedure, but Cooper recalls that most of his patients were killed by a lengthy wait. “We just didn’t have enough donors,” he says.
Today, the organ shortage is an even bigger problem than it was in the 1980s. In the United States alone, more than 114,000 people are on transplant lists, waiting for an act of tragedy or charity. Meanwhile, just 14,000 deceased and living donors give up organs for transplants each year. The supply has stagnated despite well-funded attempts to encourage donations, and demand is growing, especially as the organs of a longer-lived population wear out.
Faced with this common problem, Vacanti and Cooper have championed very different solutions. Cooper thinks that the best hope of providing more organs lies in xenotransplantation—the act of replacing a human organ with an animal one. From his time in Cape Town to his current position at the University of Pittsburgh, he has been trying to solve the many problems that occur when pig organs enter human bodies, from immune rejection to blood clots. Vacanti, now at Massachusetts General Hospital, has instead been developing technology to create genetically tailored organs out of a patient’s own cells, abolishing compatibility issues. “I said to myself: why can’t we just make an organ?” he recalls.
[...]
The ideal scaffold
While some scientists struggle to get human bodies to accept pig organs, others are attempting the more ambitious feat of engineering bespoke human organs from scratch. Such organs, grown from a patient’s own cells, should avoid the problems of immune rejection that plague the field of xenotransplantation. “Cartilage, skin, and bone are already on the market. Blood vessels are in clinical trials. The progress has been really gratifying,” says Laura Niklason of Yale University.
These tissues—either flat planes or hollow tubes—are relatively simple to produce, and consist of a small number of cell types. Solid organs, such as the lungs, heart, liver, and kidneys, pose a greater challenge. They are bigger, they contain dozens of cell types, and they have a complex architecture and an extensive network of the most essential component: blood vessels. “Every cell needs to eat and breathe, and each one needs to be close to a source of nutrition and oxygen,” says Vacanti. Still, he is optimistic that it should be possible to engineer even these complex organs. “People differ about whether it’ll be achieved in 5 or 100 years, but most people in the field believe that it’s a realistic goal,” he says.
To cope with a growing shortage of hearts, livers, and lungs suitable for transplant, some scientists are genetically engineering pigs, while others are growing organs in the lab.
For Joseph Vacanti, the quest to build new organs began after watching the death of yet another child. In 1983, the young surgeon was put in charge of a liver transplantation program at Boston Children’s Hospital in Massachusetts. His first operation was a success, but other patients died without ever being touched by a scalpel. “In the mid-80s, kids who were waiting for organs had to wait for a child of the same size to die,” says Vacanti. “Many patients became sicker and sicker before my eyes, and I couldn’t provide them with what they needed. We had the team, the expertise, and the intensive care units. We knew how to do it. But we had to wait.”
On the other side of the Atlantic, David Cooper was having the same problem. Having taken part in the first successful series of heart transplants in the United Kingdom, he had moved to South Africa to run a transplantation program at the University of Cape Town Medical School. At the time, people had a 50/50 chance of surviving such a procedure, but Cooper recalls that most of his patients were killed by a lengthy wait. “We just didn’t have enough donors,” he says.
Today, the organ shortage is an even bigger problem than it was in the 1980s. In the United States alone, more than 114,000 people are on transplant lists, waiting for an act of tragedy or charity. Meanwhile, just 14,000 deceased and living donors give up organs for transplants each year. The supply has stagnated despite well-funded attempts to encourage donations, and demand is growing, especially as the organs of a longer-lived population wear out.
Faced with this common problem, Vacanti and Cooper have championed very different solutions. Cooper thinks that the best hope of providing more organs lies in xenotransplantation—the act of replacing a human organ with an animal one. From his time in Cape Town to his current position at the University of Pittsburgh, he has been trying to solve the many problems that occur when pig organs enter human bodies, from immune rejection to blood clots. Vacanti, now at Massachusetts General Hospital, has instead been developing technology to create genetically tailored organs out of a patient’s own cells, abolishing compatibility issues. “I said to myself: why can’t we just make an organ?” he recalls.
[...]
The ideal scaffold
While some scientists struggle to get human bodies to accept pig organs, others are attempting the more ambitious feat of engineering bespoke human organs from scratch. Such organs, grown from a patient’s own cells, should avoid the problems of immune rejection that plague the field of xenotransplantation. “Cartilage, skin, and bone are already on the market. Blood vessels are in clinical trials. The progress has been really gratifying,” says Laura Niklason of Yale University.
These tissues—either flat planes or hollow tubes—are relatively simple to produce, and consist of a small number of cell types. Solid organs, such as the lungs, heart, liver, and kidneys, pose a greater challenge. They are bigger, they contain dozens of cell types, and they have a complex architecture and an extensive network of the most essential component: blood vessels. “Every cell needs to eat and breathe, and each one needs to be close to a source of nutrition and oxygen,” says Vacanti. Still, he is optimistic that it should be possible to engineer even these complex organs. “People differ about whether it’ll be achieved in 5 or 100 years, but most people in the field believe that it’s a realistic goal,” he says.
To cope with a growing shortage of hearts, livers, and lungs suitable for transplant, some scientists are genetically engineering pigs, while others are growing organs in the lab.
For Joseph Vacanti, the quest to build new organs began after watching the death of yet another child. In 1983, the young surgeon was put in charge of a liver transplantation program at Boston Children’s Hospital in Massachusetts. His first operation was a success, but other patients died without ever being touched by a scalpel. “In the mid-80s, kids who were waiting for organs had to wait for a child of the same size to die,” says Vacanti. “Many patients became sicker and sicker before my eyes, and I couldn’t provide them with what they needed. We had the team, the expertise, and the intensive care units. We knew how to do it. But we had to wait.”
On the other side of the Atlantic, David Cooper was having the same problem. Having taken part in the first successful series of heart transplants in the United Kingdom, he had moved to South Africa to run a transplantation program at the University of Cape Town Medical School. At the time, people had a 50/50 chance of surviving such a procedure, but Cooper recalls that most of his patients were killed by a lengthy wait. “We just didn’t have enough donors,” he says.
Today, the organ shortage is an even bigger problem than it was in the 1980s. In the United States alone, more than 114,000 people are on transplant lists, waiting for an act of tragedy or charity. Meanwhile, just 14,000 deceased and living donors give up organs for transplants each year. The supply has stagnated despite well-funded attempts to encourage donations, and demand is growing, especially as the organs of a longer-lived population wear out.
Faced with this common problem, Vacanti and Cooper have championed very different solutions. Cooper thinks that the best hope of providing more organs lies in xenotransplantation—the act of replacing a human organ with an animal one. From his time in Cape Town to his current position at the University of Pittsburgh, he has been trying to solve the many problems that occur when pig organs enter human bodies, from immune rejection to blood clots. Vacanti, now at Massachusetts General Hospital, has instead been developing technology to create genetically tailored organs out of a patient’s own cells, abolishing compatibility issues. “I said to myself: why can’t we just make an organ?” he recalls.
[...]
The ideal scaffold
While some scientists struggle to get human bodies to accept pig organs, others are attempting the more ambitious feat of engineering bespoke human organs from scratch. Such organs, grown from a patient’s own cells, should avoid the problems of immune rejection that plague the field of xenotransplantation. “Cartilage, skin, and bone are already on the market. Blood vessels are in clinical trials. The progress has been really gratifying,” says Laura Niklason of Yale University.
These tissues—either flat planes or hollow tubes—are relatively simple to produce, and consist of a small number of cell types. Solid organs, such as the lungs, heart, liver, and kidneys, pose a greater challenge. They are bigger, they contain dozens of cell types, and they have a complex architecture and an extensive network of the most essential component: blood vessels. “Every cell needs to eat and breathe, and each one needs to be close to a source of nutrition and oxygen,” says Vacanti. Still, he is optimistic that it should be possible to engineer even these complex organs. “People differ about whether it’ll be achieved in 5 or 100 years, but most people in the field believe that it’s a realistic goal,” he says.
That is interesting. As a guy with a pig valve in my chest, I feel a little cannibalistic when I eat bacon. I'm ready to no longer feel the guilt. [Reply]
Originally Posted by J Diddy:
That is interesting. As a guy with a pig valve in my chest, I feel a little cannibalistic when I eat bacon. I'm ready to no longer feel the guilt.
Some insects, such as bees, have a sense of smell so acutely sensitive that they can locate the faintest of odors in a room, even if it consists of only a few molecules. But scientists are particularly intrigued by the fact that these bugs can even be taught to detect various chemicals, from methamphetamines to ingredients in explosives. They’ve even been shown to effectively diagnose diseases like tuberculosis and diabetes.
U.K.-based product designer Susana Soares has created a simple, elegant way of harnessing bees to screen for a number of diseases, including cancers, like tumors of the lung and ovaries. Her glass apparatus, called “Bee’s,” features a large chamber and a smaller connected chamber housed within it. After training the bees to associate a specific chemical odor with a food reward, such as sugar, the insects are released into the diagnostic device through an opening. Patients would simply blow into the smaller compartment and wait to see if a swarm gathers toward something alarming in the person’s breath.
The project, part of her master’s thesis at London’s Royal College of Art, began in 2007 when Soares came across research on bees and their phenomenal olfactory abilities. After talking to researchers in the field, she learned that certain diseases, such as lung cancer, noticeably alter the composition of bodily fluids, producing odorous compounds that show up in urine and sometimes blood. Some investigators have even been experimenting with various sensory methods to home in on these “biomarkers.” In Philadelphia, for instance, scientists have trained mice to identify the scent of lung cancer. Trained dogs have also been used to sniff out ovarian cancer. Others have focused on replicating these animal abilities in electronic nose devices that are calibrated to pick up these biomarkers undetectable to human noses.
Insects offer key advantages over mammals and electronics, however, because of their antennae. For example, electronic nose devices have trouble detecting an odor amid more complicated conditions, like when there’s a greater mixture of gases, as is found in human breath. And studies have revealed that sniffer dogs identify odors correctly only about 71 percent of the time, while also requiring at least three months’ training. Bees, in contrast, have achieved an accuracy rate of 98 percent and can be trained in about 10 minutes.
In developing “Bee’s,” the Portuguese native needed something that enabled the user to easily transport bees into the instrument and safely suck them back out using a vacuum. The source material also had to be malleable enough to shape into a system with well-defined pathways that don’t impede their movement. She eventually settled on glass as the material because of its flexibility and transparency. “To know the results of a breath test, you’d have to see the behavior of the insects,” she says. “Everything is about their behavior.”
Prototypes have undergone field testing, and although it didn’t find any instances of cancer, it did turn up a case of diabetes that was later confirmed. It’s unlikely, though, that the concept will amount to anything beyond being an exhibition curiosity. While there was a brief period in which she felt ambitious enough to reach out to potential collaborators, the process proved so time consuming and unfruitful that she ultimately gave up. The only organizations that seemed even remotely interested in her idea were a handful of charities. So for now, “Bee’s” exists as one of those purely academic exercises to show, as she puts it, the “symbiotic relationship” humans have with nature and how “technology and science can better foster these relationships.”
“I think there’s only four labs in the world doing research into insects for disease screening, which shows you that this approach doesn’t go over well in the western world,” says Soares. “Medical and health technologies are a big business, and the bottom line is they just don’t see how something like this can be profitable.”
Glen C. Rains, an agricultural professor at the University of Georgia, largely concurs, though he adds that there are more complex issues besides economics. The entomologist, as well as licensed beekeeper, has dealt with numerous challenges while developing a similar device called the Wasp Hound, which uses a batch of five wasps to detect the presence of bedbugs. Rains’ system is a bit more elaborate in that it uses a camera to record the wasps’ behavior. The data is then fed into software that analyzes these movements to determine if the bugs actually did indeed detect these unwanted guests. After over a decade of development, Rains has forged a partnership with Bennett Aerospace, an engineering firm, to refine the technology for large-scale real applications.
“The whole notion is definitely something people find fascinating,” he says. “But once you get into how it would work or how they make money, there’s no model for how it would be done.”
While there’s a tried-and-true market for electronic technologies, Rains points out that disease screening systems based on insects requires a separate infrastructure that the industry players haven’t bothered to think through. Facilities, for instance, would need a way to efficiently obtain odor samples for training and, obviously, a beekeeper on site who can manage and train the insects. After a few positive results, the insects’ willingness to buzz towards the chemical starts to diminish significantly, as they start to catch on to the fact that a sugary reward no longer await them at the other end. Thus, in a lab setting, bugs would need constant retraining throughout the day. But what’s encouraging, he adds, is that the enlisting of bugs for clinical purposes isn’t unprecedented, with the use of maggots and leaches to clean wounds being a well-accepted medical practice.
Despite these challenges, Soares has left at least the back door open to such a possibility, if someone with the right resources is willing to take a risk. “It has the potential to save so many lives,” she says. “It can even be an open-source concept, so for anyone who is interested, I’d be happy to talk.” [Reply]
