Molecular decay of enamel-specific gene in toothless mammals supports theory of evolution

Biologists at the University of California, Riverside have found molecular decay of enamel-specific gene in toothless mammals, which provides fresh support for Charles Darwin's theory of evolution. The researchers were able to correlate the progressive loss of enamel in the fossil record with a simultaneous molecular decay of a gene, called the enamelin gene, which is involved in enamel formation in mammals. Enamel is the hardest substance in the vertebrate body, and most mammals have teeth capped with it. Examples exist, however, of mammals without mineralized teeth (e.g., baleen whales, anteaters, pangolins) and of mammals with teeth that lack enamel (e.g., sloths, aardvarks, and pygmy sperm whales). Further, the fossil record documents when enamel was lost in these lineages. "The fossil record is almost entirely limited to hard tissues such as bones and teeth," said Mark Springer, a professor of biology, who led the study. "Given this limitation, there are very few opportunities to examine the co-evolution of genes in the genome of living organisms and morphological features preserved in the fossil record," he added. In 2007, Springer, along with Robert Meredith and John Gatesy in the Department of Biology at UC Riverside, initiated a study of enamelless mammals in which the researchers focused on the enamelin gene. They predicted that these species would have copies of the gene that codes for the tooth-specific enamelin protein, but this gene would show evidence of molecular decay in these species. "Mammals without enamel are descended from ancestral forms that had teeth with enamel," Springer said. "We predicted that enamel-specific genes such as enamelin would show evidence in living organisms of molecular decay because these genes are vestigial and no longer necessary for survival," he added. Now, his lab has found evidence of such molecular "cavities" in the genomes of living organisms. Using modern gene sequencing technology, Meredith discovered mutations in the enamelin gene that disrupt how the enamelin protein is coded, resulting in obliteration of the genetic blueprint for the enamelin protein. Darwin argued that all organisms are descended from one or a few organisms and that natural selection drives evolutionary change. The fossil record demonstrates that the first mammals had teeth with enamel. Mammals without enamel therefore must have descended from mammals with enamel-covered teeth. "We could therefore predict that nonfunctional vestiges of the genes that code for enamel should be found in mammals that lack enamel," Springer said.

Short- and long-term memories require same gene, but in different brain circuits

Conducting experiments on fruit flies, a group of scientists have found that long-term and short-term memories are stored very differently because they depend upon the activity of a gene in different circuits of the brain. Assistant Professor Josh Dubnau, of Cold Spring Harbor Laboratory (CSHL), has ofund that both short- and long-term memories require the same gene, known as rutabaga, of which humans also have a similar version. He and his colleagues say that a rapidly occurring, short-lived trace in a group of neurons that make up a structure called the "gamma" lobe produces a short-term memory, while a slower, long-lived trace in the "alpha-beta" lobe fixes a long-term memory. During the study, the researchers placed flies in a training tube attached to an electric grid, and administered shocks through the grid right after a certain odour was piped into the tube. They observed that the flies with normal rutabaga genes learnt to associate the odour with the shock, and, if given a choice, buzzed away from the grid. On the other hand, the flies that carried a mutated version of rutabaga in their brains lacked both short- and long-term memory, did not learn the association, and failed to avoid the shocks. However, the researchers also found that total memory deficit did not occur when flies carried the mutated version in either the gamma or in the alpha-beta lobes. They said that restoring the normal rutabaga function in the gamma lobe caused the flies to regain short-term memory, but not long-term memory. Similarly, added the researchers, restoring the gene's function in the alpha-beta lobe alone restored long-term memory, but not short-term memory. "This ability to independently restore either short- or long-term memory depending on where rutabaga is expressed supports the idea that there are different anatomical and circuit requirements for different stages of memory," Dubnau said. His team will next try to determine how much cross talk, if any, is required between the two lobes for long-term memory to get consolidated, hoping that it may add to the progress that scientists have already made in treating memory deficits in humans with drugs aimed at molecular members of the rutabaga-signalling pathway to enhance its downstream effects. A research article describing the study has been published in the journal Current Biology.

Blind people may soon be using their tongues to 'see'

In a groundbreaking innovation, scientists have created an electronic device that may allow blind people to "see" using their tongues. The extraordinary technology works by taking pictures filmed by a tiny camera, and turns the information into electrical pulses, which can be felt on the tongue. Tests have shown that the nerves send messages to the brain, which turn these tingles back into pictures. The tool, called the BrainPort vision device, resembles a pair of sunglasses attached by cable to a plastic lollipop. Its users have revealed that they can make out shapes, and even read signs with fewer than 20 hours training only. The scientists behind this innovation say that learning to picture images felt on the tongue is similar to learning to ride a bike. The device, which collects visual data through a small digital video camera about 2.5cm in diameter, which sits in the middle of a pair of sunglasses worn by the user, could be available for sale later this year. The information is then transmitted to a hand-held control unit, which is about the size of a mobile phone. The unit converts the digital signal into electrical pulses and sends this to the tongue via the lollipop that sits on the tongue. The lollipop contains a grid of 600 electrodes, which pulsate according to how much light is in that area of the picture. The control unit allows users to zoom in and out and control light settings and electric shock intensity. "At first, I was amazed at what the device could do. One guy started to cry when he saw his first letter," News.com.au quoted William Seiple, research director at Lighthouse International, which has been testing it, as saying. Robert Beckman, president of US-based Wicab which is developing the BrainPort, said: "It enables blind people to gain perception of their surroundings, displayed on their tongue. They cannot necessarily read a book but they can read a sign." Beckman is hoping that the device would be used to improve people's mobility and safety.

'NanoPen' may revolutionise electronics sector, medical diagnostic tests

A team of scientists in California have announced the creation of a 'NanoPen' that can simplify the method of laying down patterns of nanoparticles-from wires to circuits-for making futuristic electronic devices, medical diagnostic tests, and other much-anticipated nanotech applications. Writing about their work in ACS' Nano Letters, Ming Wu and colleagues point out that researchers have already developed several different techniques for producing patterns of nanoparticles, which are barely 1/50,000th the width of a human hair. However, the researchers add, current techniques tend to be too complex and slow because they require bulky instrumentation and take minutes or even hours to complete. The researcher further point out that these techniques also require the use of very high temperatures to apply the nanostructures to their target surfaces. According to them, such limitations prevent widespread application of these techniques. They claim that their NanoPen can solve all these problems. The researchers have used the novel device in their lab to deposit various nanoparticles into specific patterns in the presence of relatively low light and temperature intensities. They say that the process, which requires the use of special "photoconductive" surfaces, takes only seconds to complete with their NanoPen. They further state that manufacturers can adjust the size and density of the patterns by adjusting the voltage, light intensity, and exposure time applied during the process.

'Telepathic' microchip can help paraplegics operate PCs, TV by thought

A British scientist has developed a "telepathic" microchip that can enable paraplegics to operate PCs and television by thought alone. Jon Spratley, 28, who works for Cornwall-based specialist engineering company 42 Technology, developed this chip while studying for a PhD at Birmingham University. He says that the chip takes advantage of the fact that even though paraplegics are unable to move their limbs, their brains still produce an electronic signal when they try. He adds that once implanted onto the surface of the brain, the chip captures this electronic "thought" and transmits it wirelessly to control a range of simple devices. He hopes that this chip may prove very help paraplegics, amputees, and those with motor neurone disease to operate light switches, PCs and even cars by the power of thought alone.pratley, from Stevenage, Hertfordshire, revealed that the main aim of his research was to "help patients communicate". "We are just trying to help people with severe communication problems or motor neurone disease - like Dr Stephen Hawking or Christopher Reeve," the Telegraph quoted him as saying. "What we have designed would allow them to control a computer with their thoughts - if they imagine their muscles moving that could flick a light switch for example," he added. Spratley, honoured with the MediMaton prize by the Institution of Mechanical Engineers, claims that implanting the chips will require minimal invasive surgery. Tests conducted in the laboratory have shown the technology to work, but human trials have not been conducted as yet.

Open-source camera may help reinvent digital photography

Stanford scientists may revolutionize digital photography with the aid of an open-source digital camera, which will give programmers around the world the chance to create software that will teach cameras new tricks. Marc Levoy, professor of Computer Science and of Electrical Engineering, says if the technology catches on, camera performance will be no longer be limited by the software that comes pre-installed by the manufacturer. He has revealed that virtually all the features of "Frankencamera" - focus, exposure, shutter speed, flash, etc. - are at the command of software that can be created by inspired programmers anywhere. "The premise of the project is to build a camera that is open source," said Levoy. Graduate student Andrew Adams, who has helped design the prototype of the Stanford camera, imagines a future where consumers download applications to their open-platform cameras the way Apple applications are downloaded to iPhones today. The camera's operating software is expected to be publicly available in a year. Users will be able to continuously improve it, along the open-source model of the Linux operating system for computers or the Mozilla Firefox web browser. Programmers will have the freedom to experiment with new ways of tuning the camera's response to light and motion, adding their own algorithms to process the raw images in innovative ways. Levoy's plan is to develop and manufacture the "Frankencamera" as a platform that will first be available at minimal cost to fellow computational photography researchers. Within about a year, after the camera is developed to his satisfaction, Levoy hopes to have to have the funding and the arrangements in place for an outside manufacturer to produce them in quantity, ideally for less than 1,000 dollars.

Vast farming projects eroding earth's surface

Mammoth farming projects can erode the earth's surface at rates comparable to those of the world's largest rivers and glaciers. A new University of British Columbia (UBC) study offers stark evidence of how humans are reshaping the planet. It also finds that contrary to previous studies, rivers are as powerful as glaciers at eroding landscapes. 'Our initial goal was to investigate the scientific claim that rivers are less erosive than glaciers,' says Michele Koppes, UBC professor of geography and lead study author. 'We found that many of the areas currently experiencing the highest rates of erosion are being caused by climate change and human activity such as modern agriculture,' says Koppes, who conducted the study with David Montgomery of Washington University. The highest erosion rates have typically been seen at high altitudes where tectonic forces pit rising rock against rivers and glaciers, says Koppes. He created an updated database of erosion rates with Montgomery, for more than 900 rivers and glaciers worldwide, documented over the past decade with new geologic measuring techniques. In some cases, researchers found large-scale farming eroded lowland agricultural fields at rates comparable to glaciers and rivers in the most tectonically active mountain belts, says an UBC release. 'This study shows that humans are playing a significant role in speeding erosion in low lying areas,' says Koppes. 'These low-altitude areas do not have the same rate of tectonic uplift, so the land is being denuded at an unsustainable rate.' The study was published online in Nature Geoscience.