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334 SCIENCE AND CULTURE, SEPTEMBER-OCTOBER, 2016 Notes and News Society in 1858 and the Crick-Watson article/letter submitted to Nature in 1953 on a suggested molecular structure of DNA. One of the most important keys for the emergence of the field of genetics occurred in 1866 when Mendel discovered the existence of genes and their transmission from generation to generation. Remarkably this year 2016 happens to be the one hundred and fiftieth (150 th ) year of publication of the famous “Experiments in Plant Hybridization”, authored by Mendel, and also 2016 marks the birth centenary year of legendary molecular biologist Sir Francis Crick (of the “Watson-Crick DNA double helix” fame). This occasion gives us an opportunity to once again fondly bring into our remembrance and recapitulate in short the contributions of Augustinian monk Mendel and English biologist Crick and pay heartfelt homage to these illustrious persons. The story of Mendel’s experiments is a highlight in the history of life science, which has become a scientific legend. In 1856, Gregor Mendel began an extensive series of careful experiments upon common edible peas, selecting 22 varieties and cross-breeding them, with the aim of determining general laws, that represent a theory of particulate inheritance, describing how the germ cells of most organisms transmit characteristics from one generation to the next. He demonstrated the action of discrete ‘factors’ (as he called them) in providing for visible traits. ‘Factors’ represent, as it was ultimately understood, specific genes, which are important functional heredity determiner. He chose to follow seven distinct traits - length of stem, seed coat colour, and so on, meticulously over the course of eight years. In 1865, he recorded and analyzed his findings in his paper “Experiments in Plant Hybridization”; he was allowed to read it as a two-part lecture before the Brunn Society for Natural History, Czech Republic, in their meetings held on 8 th February and 8 th March, 1865. In the subsequent year, in April 1866, a forty four-page article bearing the same title was published in his name in Proceedings of Brunn Natural History Society, a journal that was not much famous. Mendel asked for forty reprints of his published paper, which he soon sent to various scholars and experts in biology throughout Europe, and was dispatched to 133 other associations of natural scientists, libraries worldwide, and to scholars outside of Brunn. But his work was largely Commemorating 150 Years of Gregor Mendel’s Publication on Gene Concept and Birth Centennial of DNA Expert Francis Crick ‘Gene’ and ‘DNA’ are the two most noteworthy and fundamental words in zoology/life science, which are more appropriate in fish genetics and aquaculture biotechnology. Over the years, much progress in research and development have been made in this promising and potential-rich sub- discipline of fisheries science, leading to enhancement in fish production, exploration of newer avenues, generation of information at molecular level and enrichment of knowledge. A glimpse of it has been presented in July- August 2016 issue of Science and Culture (Notes and News section). Recent advances in our knowledge and studies on molecular biology of aquaculture species have demonstrated the potential for achieving substantial gains in aquaculture production and fisheries enhancement through application of genetics and biotechnology. Development of cutting-edge techniques in biotechnology have been assisting aquaculture for meeting the demand- supply gap and commercialization; it has led to production of improved foodfishes in terms of growth rate, food conversion, disease resistance, and product quality and composition. “Recombinant DNA technology” is such a powerful and important concept that Prof. Santosh Kumar, along with his student Manju Tembhre, begun their text book ‘Anatomy and Physiology of Fishes’ with this chapter. In present days, the terms genetic engineering, genetically- modified/transgenic organisms, gene cloning have become popular terms in improvement of economically-important plant, animal and aquaculture species and in biology as a whole; but it all originated from the pioneering works and contributions of Gregor Johann Mendel, a concept/theory on gene put forward which was further firmly established by Sir Francis Crick, thus giving birth to molecular biology and the inter-related discipline ‘biotechnology’. “Experiments in Plant Hybridization”, published in April 1866, is noted as one of the three most significant and impactful published papers in the history of life science; the other two are the Darwin-Wallace paper on evolution by means of natural selection, delivered to the Linnaean
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334 SCIENCE AND CULTURE, SEPTEMBER-OCTOBER, 2016
Notes and News
Society in 1858 and the Crick-Watson article/lettersubmitted to Nature in 1953 on a suggested molecularstructure of DNA. One of the most important keys for theemergence of the field of genetics occurred in 1866 whenMendel discovered the existence of genes and theirtransmission from generation to generation.
Remarkably this year 2016 happens to be the onehundred and fiftieth (150th) year of publication of thefamous “Experiments in Plant Hybridization”, authored byMendel, and also 2016 marks the birth centenary year oflegendary molecular biologist Sir Francis Crick (of the“Watson-Crick DNA double helix” fame). This occasiongives us an opportunity to once again fondly bring intoour remembrance and recapitulate in short the contributionsof Augustinian monk Mendel and English biologist Crickand pay heartfelt homage to these illustrious persons.
The story of Mendel’s experiments is a highlight inthe history of life science, which has become a scientificlegend. In 1856, Gregor Mendel began an extensive seriesof careful experiments upon common edible peas, selecting22 varieties and cross-breeding them, with the aim ofdetermining general laws, that represent a theory ofparticulate inheritance, describing how the germ cells ofmost organisms transmit characteristics from one generationto the next. He demonstrated the action of discrete ‘factors’(as he called them) in providing for visible traits. ‘Factors’represent, as it was ultimately understood, specific genes,which are important functional heredity determiner.
He chose to follow seven distinct traits - length ofstem, seed coat colour, and so on, meticulously over thecourse of eight years. In 1865, he recorded and analyzedhis findings in his paper “Experiments in PlantHybridization”; he was allowed to read it as a two-partlecture before the Brunn Society for Natural History, CzechRepublic, in their meetings held on 8th February and 8th
March, 1865. In the subsequent year, in April 1866, a fortyfour-page article bearing the same title was published inhis name in Proceedings of Brunn Natural History Society,a journal that was not much famous.
Mendel asked for forty reprints of his published paper,which he soon sent to various scholars and experts inbiology throughout Europe, and was dispatched to 133other associations of natural scientists, libraries worldwide,and to scholars outside of Brunn. But his work was largely
Commemorating 150 Years of GregorMendel’s Publication on Gene Conceptand Birth Centennial of DNA Expert
‘Gene’ and ‘DNA’ are the two most noteworthy andfundamental words in zoology/life science, which are moreappropriate in fish genetics and aquaculture biotechnology.Over the years, much progress in research and developmenthave been made in this promising and potential-rich sub-discipline of fisheries science, leading to enhancement infish production, exploration of newer avenues, generationof information at molecular level and enrichment ofknowledge. A glimpse of it has been presented in July-August 2016 issue of Science and Culture (Notes and Newssection). Recent advances in our knowledge and studieson molecular biology of aquaculture species havedemonstrated the potential for achieving substantial gainsin aquaculture production and fisheries enhancementthrough application of genetics and biotechnology.Development of cutting-edge techniques in biotechnologyhave been assisting aquaculture for meeting the demand-supply gap and commercialization; it has led to productionof improved foodfishes in terms of growth rate, foodconversion, disease resistance, and product quality andcomposition.
“Recombinant DNA technology” is such a powerfuland important concept that Prof. Santosh Kumar, along withhis student Manju Tembhre, begun their text book‘Anatomy and Physiology of Fishes’ with this chapter. Inpresent days, the terms genetic engineering, genetically-modified/transgenic organisms, gene cloning have becomepopular terms in improvement of economically-importantplant, animal and aquaculture species and in biology as awhole; but it all originated from the pioneering works andcontributions of Gregor Johann Mendel, a concept/theoryon gene put forward which was further firmly establishedby Sir Francis Crick, thus giving birth to molecular biologyand the inter-related discipline ‘biotechnology’.“Experiments in Plant Hybridization”, published in April1866, is noted as one of the three most significant andimpactful published papers in the history of life science;the other two are the Darwin-Wallace paper on evolutionby means of natural selection, delivered to the Linnaean
VOL. 82, NOS. 9–10 335
ignored and misunderstood. In March-April 1900, aftersixteen years of Mendel’s death, three European scientistsdoing agricultural research re-discovered his 1866 paper;they independently verified many of Mendel’s experimentalfindings. Significance of Mendel’s “Experiments in PlantHybridization” then came to the knowledge of otherscientists; it became a scientific classic, the beginning of anew approach of research. In the next several decades,scientists would learn more about genes and DNA, whichcarried specific traits of each living thing. Gregor Mendel’s1866 paper on plant hybridization formed the basis for themodern study of genes.
Born in June 1916, Francis Crick was exceptionallyintelligent and very inquisitive as a child. Determined totransit into biology from physics, in 1949, Francis Crickstarted working on X-ray crystallography to determine thethree-dimensional structures of large protein molecules(found in living organisms) at MRC laboratory of molecularbiology at Cambridge University, and was interested in howgenetic information could be stored in molecular form.DNA was recently then been shown to be responsible forhereditary control of life functions but was considered asa mysterious molecule. In 1953, Sir Crick, in associationwith Sir J. D. Watson and using X-ray crystallographic dataand model building, delineated and proposed the doublehelical structure for DNA and its replication scheme. Theysucceeded in creating a visual twisted-ladder model ofDNA.
Both of them previously realized that hereditary roleof DNA will become apparent if knowledge of its three-dimensional structure is gained, also the way genes arepassed on might also be revealed. Their classic paper waspublished in Nature on 25th April, 1953 and along withMaurice Wilkins, they shared the Nobel Prize forPhysiology/Medicine in 1962 for solving the structure ofDNA molecule, which was a revolutionary achievement andaccomplishment of a major milestone. Their DNA modelproved to fit all experimental evidence and was consistentwith its previously-described physical and chemicalproperties. It is widely regarded as one of the mostimportant discoveries in biology in twentieth century. Crickfirmly laid the foundation of molecular biology and definedthe field during its classical period, from the discovery ofthe double-helical structure of DNA to the exposition ofcomplete genetic code. He dominated intellectually thewhole field.
Mendel’s publication remained unnoticed during hislifetime but quite coincidentally, Thomas Morgan (NobelLaureate; Physiology/Medicine 1933) was born in the sameyear, i.e., 1866, who went on to make furtherance of
Mendel’s studies and tremendous contributions to ourunderstanding of the role of chromosomes and genes ininheritance. He showed that genes are linked in a serieson chromosomes and are responsible for identifiable,hereditary traits. Surprisingly Mendel, even after leading amonastic life (devoted to celibacy) in seclusion couldperform experiments so meticulously, with careful planning,based on mathematical model. It is said that Sir FrancisCrick was engrossed in editing an article on neurobiology(his future interest) on death-bed just two days before hisdeath at 88 years of age. Truly he was one of GreatBritain’s great scientist. May such people, with purededication and passion for science and innovation, becomesource of inspiration to all young readers of Science andCulture.
Subrato Ghosh122/1V, Monohar Pukur Road,
Kolkata – 700026
Not Just Toxic Elements
Chemical reactions, explosive experiments, the periodictable, elements that are too hard to pronounce, for
example praseodymium - these are things that we mostassociate with chemistry. You probably can’t remember thethings you learned during your school chemistry lessons.Most people don’t associate evcryday life with chemistry.All that comes to mind when thinking about chemistry aremad scientists. But why?
Unless you work in medicine, teach science or havea job closely related to chemistry, you will probably forgelall the things you learned at school. If the subject of aconversation is chemistry, you may struggle to engage andfind it hard to contribute. That is if you are involved inone - over half of the women in the Royal Society ofChemistry’s survey were not confident talking aboutchemistry either.
Although it is general knowledge that the right amountof chcmicals can cure illness and the matter around us ismade of elements, many people aren’t aware of how vitalchemistry is. What is unknown to you and many others isthat what seemed like useless knowledge you had to learnat school is actually a part of your daily life. I may onlybe young, but I know chemistry is not just something thatis mandatory to learn at school. It is just as helpful asEnglish and maths are.
So, if all of this knowledge is simply abandoned asyou enter your adult years, what is the point of learning
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about it in the first place? And why should you care? Tostart with, chemistry and cooking have a lot more incommon than you would originally think. If you mix all ofthe ingredients of a cake together, it won’t taste good untilit’s baked. When baked, it is the chemical reaction betweenthe individual ingredients that creates the end product. Notonly is chemistry necessary to cook food, it is just asimportant when it comes to digesting it. If you had nohydrochloric acid in your stomach you would not be ableto break down the molecules of food. The acid kills bacteriatoo.
Imagine a world where you could not lift grease andstains. Without chemistry that world would be a reality.You need soaps and detergents to break down and removethe spillages you create while eating, for example.Everything happens due to chemistry. Leaves change colour,egg can be cooked; all due to chemistry. Adults enjoydrinking wine. Without chemistry there would be no suchthing as fermentation, which means that the sugar in yourwine would not turn to alcohol. Not only does it help withall those things, but it can also keep you safe. Manyhousehold substances are dangerous to mix together, buthow will you know without chemistry? Also, it can helpyou make informed decisions; you will be able to tellwhether a product will work as promised on theadvertisement or if there is no point in wasting your moneyon it.
Famous chemists from the past such as Marie Curie,Joseph Priestley and Rosalind Franklin all discovered thatchemistry affects us even if we never have to talk about itagain. Chemistry is in our DNA - literally! From x-rays tothe air we breathe, they realised that it is everywhere. Ithink the reason not many people associate chemistry withthings we do every day is because it is not obvious. Likea code, it is encrypted into everyday objects and you willonly realise it if you look closely. If you could see all thethings chemistry does for us, if you could see what lifewould be like without chemistry, then everyone would tryto remember all the things their teachers told them at schoolabout the science. You may think that all the aspects ofchemistry involve explosions and toxic substances, butsome of the best chemical reactions happen in your ownkitchen.
Leah YoungOriginally published in Chemistry World,www.chemistryworld.org. The author from Sheffield, U.K.is this year’s Chemistry World science communicationcompetition winner in the new Rising Star category under-16s.
Why are the public views of these two fundamentallylinked disciplines so conflicting? This is one of the moreconcerning findings within the Royal Society of Chemistry’sPublic attitudes to chemistry research report.1,2
If we take the traditional view of science as thecombination of biology, chemistry and physics, it’sinteresting to consider how these other two branches wouldcompare to the same line of questioning. Owing to theirsuccess in mainstream media, I suggest that both biologyand physics may come across better than chemistry.
The report states that 57% of those questioned heartheir chemistry stories via television more than any othermedium, most commonly through news programmes.1
These are designed to be informative, rather thanentertatining. Biology has held a long-standing relationshipwith television and reaches huge audiences via the nationaltreasure that is Sir David Attenborough. Physics,meanwhile, is undergoing something of a TV revolution,with Brian Cox at the helm ; followed by Chris Hadfield,Tim Peake, The big bang theory.... the list goes on. Theawe-inspiring cinematography in nature and spacedocumentaries, the cuteness of the animals, the personalitiesof the presenters – all of these things ensure that theviewers attention is hooked. They now want to hear thescientific meassages that follow. So far, chemistry is yet toachieve this with a popular television show.
The power of the so-called ‘Brian Cox effect’ wasevident in 2012 with the discovery of the Higgs boson.The news was everywhere. You couldn’t turn on the TVwithout hearing about the Large Hadron Collider. Very fewcould tell you what the Higgs boson actually was, butimportantly, we had heard of it. More importantly, we knewthat it was physics. Would the media reaction to this newshave been the same had it occurred 10 years earlier, beforeBrian Cox ? I doubt it.
Who is there to represnet chemistry, the forgottenmiddle child ? Chemistry needs a public champion,someone to bring it to life, someone to ignite the sameresurgence we have seen in physics. The closest it has comeis Breaking bad’s methamphetamine-producing WalterWhite, but that’s probably not the side of chemistry thatwe should be encouraging!.
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The challenge lies within the subject itself. Thedifferent aspects of chemistry are all intrinsically linkedby underlying concepts. This makes it fascinating to some,but confusing for others. What is an atom? What is amolecule? What are electrons? These and many otherfundamental questions need to be answered before the storycan be fully appreciated. This makes it difficult to breakdown into bite-sized chunks without discussing thefundamental narrative that underpins them; a certain degreeof background knowledge is required before the mostinteresting applications can be appreciated. The problemcan be traced back to the modular way that chemistry istaught in schools. It’s forcibly broken down into separateblocks and the overall story is lost. The long term solutionmay involve rethinking the way in which we teachchemistry. Chemistry is a very visual subject (who doesn’tlove bangs and flashes?), but it’s difficult to translate anexplosion or dramatic colour change into the theoreticalreaction that has taken place. We can see the result of thereaction, we saw the explosion, but we can’t see the bondsbetween the atoms breaking and re-forming. Chemistry isextremely conceptual, and the underlying story is hard tounderstand, relying on sophisticated mental models. Thisis why bangs and flashes shows have previously been sosuccessful. They have the wow factor that hooks theaudience’s attention, before discussing the theoretical side.But do we have such little faith in chemistry that we thinkfor an experiment to be considered interesting, it needs toexplode ? The dangerous nature of these shows does notencourage participation, contributing to chemistry’sinaccessible image. You can’t promote interest in a scienceby telling prople ‘don’t try this at home!’. I think thisapproach may have had its day. It appears to be contributingto the problem, and a new idea is required. Physics hadmanaged to bring a sub-atomic particle to life. Now it’sour turn.
Chemistry is constantly occurring around us, invisibly,every day. From the amphiphilic molecules in washing upliquid to the benzophenones in sun cream, it goes largelyunnoticed. There are many clever and fascinating storiesto be told but, unfortunately, perhaps chemistry has becomea victim of its own prevalence. We don’t realise that it’schemistry; it’s just ‘how the world works’. We need tomove beyond the bangs and flashes and find ways of tellingsome of these incredible stories that have a huge impacton out daily lives. Using the media as a catalyst, theexcitement can be found, not from explosions, but fromthe chemistry itself.
1. Royal Society of Chemistry and TNS BRMB, Public attitudesto chemistry 2015.
Ben StutchburyOriginally published in Chemistry World,www.chemistryworld.org. The author from Sheffield, U.K.is this year’s Chemistry World science communicationcompetition winner.
Names of Four New Elements Announcedby IUPAC
After reports of the discovery of four new elements,all of synthetic origin, during 2004-2012, followed
by validation of the claims by the International Union ofPure and Applied Chemistry (IUPAC) over a period of threeyears, the IUPAC accepted in December last year (seeScience and Culture, March-April issue, No. 3-4, 2016, p.119) their tentative names (and symbols) as Ununtrium(Uut), Ununpentium (Uup), Ununseptium (Uus) andUnunoctium (Uuo) for the elements with atomic numbers113, 115, 117 and 118, respectively. Following thestipulation that new elements may be named after ascientist, a geographical place, a property of the element,a mineral or a mythological figure or concept, thediscoverers named the respective elements (and theirsymbols) as Nihonium (Nh), Moscovium (Mc), Tennessine(Ts) and Oganesson (Og).
The element 113 was discovered in Japan, hence thename ‘Nihonium’ which means “the land of the rising sun”.The names ‘Moscovium’ (for element 115) and ‘Tennessine’(element 117) are named after Moscow and Tennessee,respectively where they were discovered. The nameOganesson (element 118) is in recognition of its discoverer,the Russian chemist Yuri Oganessian.
Unless challenged during a 5-month public commentperiod ending in November this year, the new names willthen be officially entered into the Periodic Table.Pertinently, the name Nihonium, if ratified in due course,will be the first east Asian name to appear in the PeriodicTable.
Professor Manas Chakrabarty, FRSCFormerly, Department of Chemistry,
Bose Institute, Kolkata
338 SCIENCE AND CULTURE, SEPTEMBER-OCTOBER, 2016
De Novo Synthesis of Human Beings –Human Genome Project-Write
Sounds silly? Don’t worry, nobody is trying to make anarmy of clones or start a new era of eugenics. The
fact is that a group of scientists have proposed to synthesisethe entire human genome from scratch, hence the crypticcaption.
On June 2, 2016 a 25-member team led by Jef D.Boeke, Director of the Institute of Systems Genetics, NewYork University, N.Y., George Church of Harvard MedicalSchool, Boston, MA, Andrew Hessel, Autodesk Research,San Rafael, California and Nancy J. Kelley, formerlyExecutive Director, New York Genome Center formallyannounced (Science, http://dx.doi.org/10.1126/science.aaf6850, 2016) their proposal to synthesise theentire 3-billion-base pair human genome from scratchwithin the next ten years. They dubbed their project asHuman Genome Project-write (HGP-write).
This announcement was indeed the follow-up of twoearlier meetings – the first one being held at the LangoneMedical Center, New York University on October 31, 2015and the second, invitation-only, closed door meeting beingheld at Harvard Medical School on May 10, 2016. Thelatter meeting was attended by 130 scientists, entrepreneurs,lawyers and ethicists. According to the proposers, thecurrent technologies available for the synthesis of genomeswould be too expensive to synthesise the gigantic genome.The main aim of the HGP-write is, they say, “to reducethe cost of engineering and testing large (0.1 to 100 billionbase pairs) genomes in cell lines by over 1000-fold within10 years.” The project will be administered by a non-profitorganisation, viz. the Center of Excellence for EngineeringBiology.
The project is estimated to cost less than $ 3 billionwhich was the cost of the earlier Human Genome Project-read (HGP-read) aimed at reading, i.e. sequencing thehuman genome and improving the technology, cost andquality of DNA sequencing. But the team intends to initiallycarry on a series of pilot projects on the synthesis of muchshorter segments of the genome and on the making ofdownsized chromosomes designed to do specific tasks sothat the ultimate goal can be materialised. They hope toraise $ 100 million by the end of 2016 when they canstart the initial work. The proposers stated that Kelley willbe the top executive for the project, and that Autodesk hascommitted $2,50,000 in funding for the planning efforts.
The announcement of HGP-write received mixedresponses - criticisms as well as praises. Drew Endy, an
Associate Professor of bioengineering at StanfordUniversity, and Laurie Zoloth, a bioethics Professor atNorthwestern University, Evanston, Illinois said that theHGP-write team has not justified its aims properly and theproject should be abandoned. Endy wrote on Twitter, “Ifyou need secrecy to discuss your proposed research(synthesizing a human genome), you are doing somethingwrong.” Some people apprehended that the syntheticgenome could be used to create human beings withoutbiological parents. Francis Collins, the Head of the NIH,said that it is premature to launch such an initiative.Ironically, Collins had headed HGP-read. Some others feelthat the project is a needless centralisation of work that isalready going on in other companies involved in reducingthe cost of synthesising strings of DNA.
Many others have, however, praised the project. Forexample, Paul Freemont, a structural biologist at ImperialCollege, London said, “I think, it’s a brilliant project”.Danielle Tullman-Ercek, a biochemical engineer at theUniversity of California, Berkeley said that this project haspractically unlimited potential for indirect products. Tosome, the proposal is praiseworthy even because of its sheerambition since de novo synthesis of only tiny bacterialgenomes and a portion of a yeast genome have beenachieved so far.
Boeke, who had synthesised in 2014 the 0.27 million-base pair yeast chromosome (N. Annaluru et al., Science,344, 55 (2014); doi: 10.1126/science.1249252), brushedaside all the criticisms and misgivings about the project.Regarding secrecy, he said that much of the second meetingcentred round the ethics of the project. He also added thatsome portions of the fund should be directed towardsaddressing the ethical, legal and social issues concerningthe project, and that there should be no intellectual-propertyrestrictions on the products of HGP-write (just as in thecase of HGP-read). He envisions that the project will leadto cheaper synthesis of genomes, and the likely benefits tobe accrued thereof include growing transplantable humanorgans, engineering immunity to viruses (in cell lines),engineering cancer resistance to therapeutic cell lines,accelerating cost-efficient vaccines and development ofpharmaceuticals (using human cells and organoids).
The concluding remarks of the proposal are: “wecelebrate 2016 – the 25th anniversary of HGP-read – as amajor step forward for human knowledge and health. Inthis spirit, we look forward to the launch ofHGP-write”.
Professor Manas Chakrabarty, FRSCFormerly, Department of Chemistry
Bose Institute, Kolkata
VOL. 82, NOS. 9–10 339
Moon has Plenty of Water
Till India’s Chandrayaan-1 first detected presence ofwater on Moon in 2008, Earth’s closest neighbour was
believed to be bone dry, based on rocks brought back byNASA’s Apollo lunar missions starting in the late 1960s.Soon NASA also corroborated the findings ofChandrayaan-1 indicating that the Moon indeed has water.In recent years, more advanced techniques have actuallypicked out significant signs of water in those lunar samplesand scientists say, “Though the surface is parched, the lunarinterior might actually have about 10,000 to 10 milliontimes more water than the surface seems to hold”. A recentstudy suggests that most of the water inside the Moon musthave been delivered by asteroids some 4.5 to 4.3 billionyears ago, when its molten oceans were hit by asteroidscarrying water (Nature Communications, 31 May 2016 |DOI: 10.1038/ncomms11684).
New research finds that asteroids delivered as much 80 percent of theMoon’s water. (Credit: LPI/David A. Kring)
For the study, an international team of researchers ledby Jessica J. Barnes of The Open University, in the UKcompared data from a range of different studies that hadanalysed lunar samples brought back from the Moon ormeteorites (which are thought to be chunks of asteroidsthat fell to Earth). The researchers studied the compositionof certain elements in the space rocks, especially the ratioof hydrogen-to-deuterium (a heavier isotope of hydrogen),which allows them to figure out the origin of Moon’s water.They found the hydrogen-to-deuterium ratio to be similarto that of a certain type of asteroids known as chondrites.
After carefully collecting and modelling the data, theresearchers found that the Moon’s water probably camemostly from asteroids – even though comets have thereputation for being rich in water ice. From about 4.5 to4.3 billion years ago, the researchers say, more than 80%of the Moon’s water likely came from various types ofasteroids and less than 20% of it came from comets. Back
then, the young, hot Moon was covered in a magma oceanand the asteroids would have sunk into the fluid mix. Inaddition to asteroids and comets, the researchers say, it isalso likely that some of the water inside the Moon may bederived from the early Earth during the Moon-formingimpact event.
According to the researchers, after the Moon was bornof a collision between Earth and a Mars-sized planet some4.5 billion years ago, it was bombarded with water-richasteroids known as carbonaceous chondrites for tens ofmillions of years, may be even longer, which delivered alot of water to the Moon. Incidentally, Earth also got mostof its water from asteroid bombardment.
The researchers estimate that the lunar interior couldcontain “of the order of 1,000 trillion tonnes” of water,probably locked inside minerals in the form of hydroxyl(OH) ions. On the surface, they estimate, “up to a billiontonnes of frozen water – enough to fill a million Olympicpools – is probably lodged as ice inside deep craters aroundthe north and south lunar poles, where the Sun’s rays neverpenetrate”. It is one of the reasons several spaceagencies – including the European Space Agency andNASA – are currently developing robotic missions toexplore new regions on the Moon to better estimate thequantity of ice. They conclude that the water “has beentrapped there for three or four billion years”.
Biman BasuDream 2047
August 2016, Vol. 18 No. 11
How the Giraffe Got its Long NeckRevealed
One of the most distinguishing features of the giraffeis its extraordinary long neck, which accounts for
almost half of its height. Interestingly, unlike some speciesof long-necked birds, which have up to 25 vertebrae intheir cervical spine, the giraffe has only seven of thesebones – the same as we humans have. To compensate forthe extra height, the giraffe has a blood pressure level twotimes higher than humans, powered by an extra-large heart,to reach blood to its brain.
There have been many hypotheses to explain theextra-long neck of the giraffe. The 18th century Frenchnaturalist Jean Baptiste Lamarck believed that the longnecks of giraffes evolved as generations of giraffes reachedfor ever higher leaves on trees. He suggested that if agiraffe stretched its neck for leaves, for example, a “nervous
340 SCIENCE AND CULTURE, SEPTEMBER-OCTOBER, 2016
University, “These adaptations include unique amino-acid-sequence substitutions that are predicted to alter proteinfunction, protein-sequence divergence, and positive naturalselection”. Over half of the 70 genes code for proteins thatare known to “regulate development and physiology of theskeletal, cardiovascular, and nervous system” – just the typeof genes predicted to be necessary for driving thedevelopment of the giraffe’s unique characteristics.
The okapi is the nearest relative and the only other surviving member ofthe family Giraffidae.
Among the genes showing multiple signs of adaptationin the giraffe the research team also discovered severalgenes known to either regulate the development of thecardiovascular system or to control blood pressure. Someof these genes control both cardiovascular development andskeletal development, suggesting the intriguing possibilitythat the giraffe’s stature and powerful cardiovascular systemevolved as a result of changes in a small number of genes.
According to the researchers, for the giraffe’s necksto grow so long, two crucial things need to happen: First,the genes that tell the neck when to stop growing neededto be turned off; second, genes that promote growth needto be upregulated; that is, need to increase the response toa stimulus. They singled out one gene in particular,FGFRL1, as playing a key role in promoting neck growth.The gene is responsible for adaptions unique to giraffes,especially for regulating embryo development andparticularly the skeletal and cardiovascular systems. Alsoof importance are four so-called “homeobox” genes (a classof closely similar sequences that occur in various genesand are involved in regulating embryonic development ina wide range of species) that come into play during thegiraffe’s development from an embryo into adolescence.These four genes also have unique adaptions that theresearchers think promote rapid growth in the giraffe’scervical vertebrae.
Biman BasuDream 2047
August 2016, Vol. 18 No. 11
fluid” would flow into its neck and make it longer. Itsoffspring would inherit the longer neck, and continuedstretching would make it longer still over severalgenerations. Of course, today we know that it does nothappen like that. Recently, scientists seem to have found agenetic clue.
Scientists have found a genetic link to giraffe’s long neck.
To figure out just how the giraffe got its long neck,researchers from the Giraffe Genome Project – a jointventure of Penn State University in USA and the NelsonMandela African Institute for Science and Technology inTanzania – sequenced and compared the giraffe genometo that of the okapi, their nearest relative and the onlyother surviving member of the family Giraffidae. Theanalysis revealed the first clues about the genetic changesthat led to the evolution of the giraffe’s exceptionally longneck. The okapi is a herbivore found in tropical mountainforests of Central Africa. Despite its deer-like appearancethe okapi is actually one of the last remaining ancestorsof the giraffe, which is the tallest animal on Earth. Theresearchers say that giraffes and okapi split around 11.5million year ago, after which the giraffe underwent atremendous growth spurt.
Using a battery of comparative tests the researchersshortlisted 70 genes that showed multiple signs ofadaptations. According to Douglas Cavener of Penn State