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First human migrated to Andamans from Africa “Anti-ageing” system
Tomato gene sequencing Biological arms race goes on
THIS UNIVERSE |
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First human migrated to Andamans from Africa
GENETICISTS at the Centre for Cellular and Molecular Biology (CCMB), Hyderabad, have established through DNA analysis that the early human had “first” migrated out of Africa taking the “South route” via India to reach Andamans Islands, some 70,000 years ago. Reconstructing the pre-historic human colonisation of the world, the CCMB geneticists claimed that their studies of the maternally inherited mitochondrial DNA (mtDNA) had established that modern human arose possibly about 1.5 lakh years ago from East Africa and had reached the Andaman Islands by taking the route along the Indian Coast. They later reached Nicobar Islands as well. “Our study suggested that the Onge and the Great Andamanese are unique in their origin,” CCMB Director Lalji Singh, who unveiled the findings after a “complete mtDNA analysis” of 16,569 base pairs of five each of Onge, Great Andamanese and Nicobarese, has claimed. “Novel mutation found by us in mtDNA of the Onge and Great Andamanese helped in placing them in two unique branches — defined as M31 and M32, for the first time in the world by CCMB — in the human evolutionary tree”. The three-year CCMB study, led by Dr K Thangaraj, reconstructed that some modern humans, who came out of Africa over 70,000 years ago and ventured into the northern coastal areas of Indian Ocean, finally reached Andaman Islands. The two ancient maternal lineages had evolved in the Andaman Islands in genetic isolation, independently from other South-East Asian population, the study, which was reported in the prestigious ‘Science’ journal, suggested. Dr Lalji Singh explained that there were two distinct tribes in the Andaman and Nicobar Islands - Nigrito - who shared physical features such as short stature, dark skin, peppercorn hair, scant body hair with African pygmies and other Asian Negrito people, and - Mongoloid - who shared physical features with the Chinese, Malays and Burmese. They spoke dialects related to Mon-Khmer and languages spoken in Vietnam, Malaysia and part of north east India. “The origin of the Andaman “Negrito” and Nicobar “Mongoloid” populations has stimulated a wide range of speculation. Their origins are really a mystery. No one knows where they came from. How long had they been there? Could these Islanders hold the key to the mystery of our own origins? Their world could serve as a window to look into the past showing us how we (humans) were, hundred thousand years ago, when the first modern humans left Africa”. “We have used the mtDNA sequence to trace the emigration of Andamanese because of the existence of the traces of errors (mutations) that slowly accumulated in certain regions of the mitochondrial genome”. “After a population splits, the people who go east will gain a different set of errors (mutations) from those who venture west. From the population splits, implied by these error patterns, family trees of different lineages can be reconstructed in the grand genealogy of the human kind, and even rough dates to the evolutionary branch points can be assigned as each mutation takes place on a specific time scale”. “Since mtDNA was inherited only through the mother, it was useful to trace the maternal lineages”. Comparison of the complete mtDNA sequences of the Onge and Great Andamanese with the mtDNA sequences of the populations known so far across the world had revealed that the mitochondrial DNA sequences of the Onge and the Great Andamanese did not match with any of the populations, including 6,500 samples covering the entire Indian subcontinent.
— UNI |
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“Anti-ageing” system WITH newer beauty products hitting the market every other day with claims to give a “younger” look, the National Botenical Research Institute (NBRI) has developed a novel herbal “anti-ageing” system that detoxifies human cells and restore their ability to reproduce and remain “young”. “The Enzymatic Antioxidant System, the scientific name for this herbal formulation, took alomost three years to develop, NBRI Director Dr Pushpangandan told pressman in Lucknow. “It had recently been granted a global patent,” he added. The system reportedly rids human cells of free radicals, thereby helping reducing the incidence of wrinkles and scars, heal wounds and strengthening hair roots. Project Leader Dr V.K. Kochhar said the system could effectively be used in a veriety of skin Products such as face pack and scrub, cream, lipstick, hair oil, shampoo, after shaves, etc. “Talks are on with some major international and Indian cosmetic companies for the commercial application of the system,” he said adding products based on the system would surely hit the market by the year-end.
— UNI |
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Tomato gene sequencing
INDIA, with nine other countries, has started gene sequencing of tomato as part of an international project aimed at increasing the vegetable’s yield, nutrition and disease resistance properties. The process, which is likely to be completed in the next five years, would serve as a global source of information on tomato and help improve its nutritional and disease resistant varities, Prof Akhilesh Tyagi of the Department of Plant Molecular Biology, University of Delhi, has said. “Full genetic information of tomato will greatly enhance conventional breeding strategies and enable the generation of new crop varities with improved disease resistance,” he said adding yield increase was the foremost concern. After completion, the project would help scientists pinpoint desirable characterstics in the genetic makeup of the tomato that could be introduced into other plant varieties . Tomato, a significant commercial crop worldwide, is a model plant species for studying quality traits in all fleshy fruit bearing plants, he said adding: “Beta carotene, that is found in tomato, is known for its anti-cancerous quality.” Its qualities such as preventing heart disease and boost immunity could also be introduced in other plants, he said. Information about the gentic makeup of tomato and utilisation of the available knowledge base to improve the quality of the vegetable are the two components the scientists, at present, are looking at, he said.
— PTI |
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Biological arms race goes on
ALTHOUGH echolocation provides some bats and whales with an extraordinary capability to detect and track their prey, a few of those creatures’ favoured meal items have developed techniques to counter that advantage. A diverse group of insects, including beetles, katydids, lacewings, and a host of moth species, have body structures that vibrate when struck by the ultrasonic frequencies used by echolocating bats, says M. Brock Fenton of the University of Western Ontario in London. Equipped with these sonar detectors, the insects can engage in a variety of countermeasures. The easiest — and typically most effective — move is simply to turn tail and fly away before detection. For example, some moths can perceive a bat’s ultrasonic chirps from a distance of 40 metres, about four times the distance at which the bat can detect the moth, Fenton notes. When sonar signals get stronger, suggesting that a prowling bat is close, insects may fly upward in a spiral, flutter their wings chaotically, or fold their wings and dive to the ground. Some moths use all these tricks, says Karry A. Kazial of the State University of New York at Fredonia. Randomly using different techniques adds a further measure of unpredictability to a moth’s behaviour, she notes. Some insects have evolved to emit high-pitched squeaks of their own, signals that may disrupt the bat’s sonar. Kazial says that she considers that possibility unlikely, however, because tests suggest that such a jamming technique would work only if the defensive chirp were emitted just as the bat’s sonar pulses were bouncing off a moth, for instance. Instead, the defensive squeaks may serve as a warning that the moth is distasteful — an audible version of the protective coloration of some bitter-tasting butterflies and poison frogs. |
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New Products and Discoveries Robot arm for monkeys The finding has profound implications both for understanding the extraordinary adaptability of the primate brain and for the potential clinical success of brain-operated devices to give the handicapped the ability to control their environment, said the researchers. The researchers first implanted an array of microelectrodes - each thinner than a human hair - into the frontal and parietal lobes of the brains of two female rhesus macaque monkeys. The faint signals from the electrode arrays were detected and analyzed by the computer system the researchers developed to recognize patterns of signals that represented particular movements by an animal’s arm. Early Egyptian sailors On Christmas Day last year, Kathryn Bard got an unusual gift. Working with her colleagues to remove sand from a hillside along Egypt’s Red Sea coast, the Boston University archaeologist poked through a small opening that had appeared and felt . . . nothing. She had reached into the entrance to a human-made cave in which sailors stored their gear as many as 4,000 years ago. Two days later, Bard’s team found a larger cave nearby. The same ancient seafarers used this one, she and her colleagues surmised, as a temple or shrine. Rice fungus genome Scientists have unravelled the genome of the rice plant’s greatest fungal menace, a harvest-wrecking foe that each year destroys the potential to feed 60 million people. Magnaporthe grisea is the first pathogenic plant fungus to have its genetic code unravelled, a feat that the researchers hope will open the way to newer, smarter and less damaging weapons against this manace. M.grissa, also called rice blast, comprises windborne epores that stick to the leaves of the rice plant thanks to a special adhesive on the spore tip.
— AFP |
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THIS UNIVERSE Q Electricity is due to flow of electrons. Once the electron is taken away then what will happen to the left behind positively charged atom? A An electrical circuit is a closed loop. For example, when a battery is connected in a circuit with a resistance, say a lamp, current flows around. If you concentrate on electrons, they flow from the negative terminal, through the bulb back into the battery through its positive terminal. Electrons are not going away and permanently leaving the nuclei unclad. As one electron moves, another takes its place. While travelling, the electrons interact with the lattice of atoms in the filament of the lamp, resulting in resistance and the production of heat and light. They do not go and sit there. A simple analogy might be the following. Imagine that we have a ring of a large number of dancing boys and girls. In this dance, the girls are handed over from one boy to the next, going in a circle. This “current” of girls might raise up a lot of dust on the way, but at no point would any of the boys be found without a girl next to him. A force akin to the electromotive force would, of course, be needed to keep the girls moving, overcoming the resistance along the path. Unlike the girls in this example, the electrons are all identical and the nuclei will never be able to “tell” that they lost their companion for a even a moment and got another one in its place! There is another fact that has to be understood. In metals, the atoms in crystals live in cooperative colonies. The electrical fields in these crystals are such that some electrons residing therein do not know or care about who their parent nuclei are. Periodic potential of the crystalline structure, coupled with the Pauli principle and quantum considerations help us to understand the sub-division of materials into conductors, semiconductors and insulators. (The band gap of the semiconductors, that are at the base of all solid-state electronics industry, also comes out of theory.) Q Why does Saturn have rings around it? A Saturn is rather unique in respect of its rings. These have been observed at close quarters by the Voyager space probe over 20 years ago and found to be more complex in their structure than was earlier believed. The rings are thin. A spacecraft can go through them without any real danger of collision. They probably consist of water ice and ammonia ice. There might also be some dust and stones. Most particles are small but some might be as large as a few metres. Some of Saturn’s moons are quite close to the rings and might have some influence on their shape and stability. The particles in the rings are essentially independent satellites. It seems that larger stones act as shepherds to maintain the ring-like structure. But the question still remains as to why only Saturn should have this fantastic decoration. I do not know whether one can give a definitive answer. Maybe a satellite planet or moon broke up in its neighborhood and the debris spread out as a ring. Could there have been a large comet that was accidentally captured by Saturn and then slowly disintegrated? The fact that there is an abundance of water ice in the rings might favour the comet hypothesis. Frankly, I do not know the answer. I doubt if any one else knows for sure. It might be worth pointing out that the thinness of the rings is due to the combined effects of the mutual gravitation of the particles of the rings and centrifugal force. |
MONKEYS that learn to use their brain signals to control a robotic arm are not just learning to manipulate an external device, Duke University Medical Center neurobiologists have found. Rather, their brain structures are adapting to treat the arm as if it were their own appendage.