SCIENCE TRIBUNE Thursday, February 15, 2001, Chandigarh, India
 


Human genome: what it reveals, and hides
by Amar Chandel
T
HE "book of life" called the human genome was expected to be the world's greatest history book, but it is turning out to be a mystery thriller instead. The more of it is being unravelled, the more puzzling and complex the plot is becoming.

Earthquake preparedness
by G.S. Dhillon
T
HE devastation wrought by the Bhuj earthquake of January 26 has shown that there is an urgent need for creating greater awareness about earthquakes and to impart training for better preparedness to meet disaster situations, so that loss of human lives is reduced to the bare minimum.

SCIENCE QUIZ
 


   
 
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Human genome: what it reveals, and hides
by Amar Chandel

THE "book of life" called the human genome was expected to be the world's greatest history book, but it is turning out to be a mystery thriller instead. The more of it is being unravelled, the more puzzling and complex the plot is becoming.

When it was announced in June last year that the human genome had been sequenced, it was thought that the "holy grail" of human body and personality had been found. Now that the information is out in the public domain and preliminary analysis has been done, it is being conceded that some of the secrets may never be fully out. The DNA code may not explain things like how personality and intellect arise.

Members of the two teams that decoded the genome admit that in principle, the string of genetic bits holds long-sought secrets of human development, physiology and medicine. But in practice, our ability to transform such knowledge into understanding remains woefully inadequate. Dr J. Craig Venter, president of Celera and lead author of the paper in Science, laments: "We feel like midgets describing the universe and we cannot comprehend it all". The effort to sequence and interpret the human genome has been mentally exhausting because we are not mentally equipped to absorb all this, concedes the scientist with a computer centre as big as a football field to crunch the genetic information.

It is now clear that tiny changes in the sequences of the A's, T's, C's and G's that make up DNA can lead to quite different results. The human gene sequence has given us the code for the human genetic map. If printed in standard type, it will fill 75,490 pages of this newspaper. Now this code has to be broken.

The attempt to know the functioning of the miracle called the man is being likened to figuring out how a large corporation works only by scrutinising its telephone directory. The names and locations of a large number of people are available. But it is not clear what each of them does, how they work together to get things done or what employees or teams are at fault when something goes wrong.

The limited capacity of the human mind to comprehend the ways of nature has been exposed in the preliminary stage itself. Many of the expectations of the scientists have been belied. For one thing, the very number of genes that people have has been found to be far short of expectations. While scientists were earlier of the opinion that there may be more than 1,00,000 genes, the number actually may be only between 26,000 and 40,000. When the completion of the rough draft of the human genome was announced last June, scientists had thought that 97 per cent of human DNA was so-called "junk" DNA, without any important function. Now they believe that the "junk" DNA does have functions, one of which may be to move genes around. However, nearly 40 per cent of the genes are still a total mystery, with no known function. As one scientist has aptly commented, we may hail our achievements as spectacular, but scientists 50 years in future will see the two papers published this week as the "documented ignorance of how little we know in 2001."

Equally astonishing is the similarity in the genomes of people of different races. In a way the cellular structure of all human beings is almost similar. Mathematically, we are all virtually identical twins, says Dr Venter. All humans share 99.9 per cent of their DNA. Racial and ethnic designations thus have no scientific basis. It is the 0.1 per cent of the DNA with subtle differences that makes individuals unique, including their susceptibilities to disease.

For that matter, we the human beings may not have genes much in excess of worms and fruit flies. A roundworm has 19,000 genes, the fruit fly 13,000. The human genome has only a few hundred genes that are not there in the genomes of mice, rats and dogs. Dr Venter says he has found only 300 human genes that had no counterpart in the mouse genome. This notion of evolution as a constant reworking or random recombining of parts is in a way the confirmation of Darwin. But the message is clear: more than the genes that control production of the proteins, we will have to understand the proteins that make up people. Mankind now requires an insight into the mystery as to how human beings, who are so complex, can manage with only a relatively modest number more genes than worms and flies.

Another big surprise is that about 200 human genes apparently arose from genes that were somehow inserted into humanity's early vertebrate ancestors by bacteria.

Nevertheless, the sequencing of the 3.2-billion "letters" of the human DNA code, a long twisting chemical ladder that contains the basic instructions for building and running a human body, is a historic event, which can be bracketed with the discovery of electricity or the landing on the moon because it has the potential to change the future of mankind. Endless vistas in science and medicine that it has opened are fenced only by the limitations of our imagination.

The most tantalising advances are expected to take place in the field of medicine. Scientists will focus on five common health problems: heart problems, cancer, diseases afflicting the nervous system, environmentally linked illnesses and infections.

Both teams that largely decoded the genome say their results have already helped others to find dozens of disease-promoting genes. All along, we have been given one-size-fits-all sorts of drugs. In future, genomics-based medicines may be as person-specific as one's fingerprints. These will attack only the disease and leave the rest of the body alone. Side-effects will become a thing of the past.

All this will happen on the Internet at the click of a computer mouse. For instance, it took two scientific teams 10 years to isolate the gene that causes cystic fibrosis when defective. Now that the DNA has been sequenced and mapped, a comparable research could be finished by a single graduate student in about two weeks.

Human genome is like an automobile manual used by mechanics to determine what is wrong with a car that is not running properly. It is now accepted that mutations in the genome predispose or cause at least 1,500 diseases. Not only can diseases like cancer and Alzheimer's become curable, even personality disorders like addiction, criminality or antisocial personality may become surmountable by recognising the rogue genes and determining what and how they went wrong.

Researchers may be able to identify genes that predispose some people to quickly become alcoholics or addicted to cocaine or heroin. About 50 per cent of the risk of addiction may be genetic.

A genetic panacea for all of crime may not be available, but there is a possibility that there may even be genes that help explain why some people become violent criminals while others living in the same conditions do not. But in the euphoria, what should not be forgotten is that the brave new world is not going to be with us tomorrow. The human genome is so complex and so much work remains to be done that it may be years - even decades - before the benefits start to flow our way.

In any case, the average cost of bringing a new drug to the market is likely to double from $ 800 billion in the year 2000 to $ 1.6 billion in 2005 before falling to $ 1 billion in 2010.

Nor are the genes the final answer to treating disease. A mutated or changed gene gives one a predisposition for a particular disease. It takes an "environmental insult", like smoking, to trigger the predisposition towards that disease (say, cancer). So, the focus will be on advances in prevention and lifestyle choices.

Genome work will also help scientists evaluate environmental hazards and study human evolution and migration.

While we anticipate a disease-free world of tomorrow, fears have gripped a sizeable section about the likely negative effects as well. Easy availability of human genome can also lead to the possibility of developing a race whose members may differ from each other very little and may be raised to perform only specific tasks.

Even otherwise, there is a hue and cry that the details of one's genetic makeup should be a secret, otherwise information about an individual's lifetime risk of cancer, heart attack or other diseases could be used to discriminate in hiring, promotions or insurance. Many experts are clamouring for stringent laws to specifically prohibit such potential discrimination, infringing on human rights, fundamental freedoms and human dignity. All such legal, ethical and social implications should be taken into account while the strings of genetic bits yield long-sought secrets of human development, physiology and medicine.

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Earthquake preparedness
by G.S. Dhillon

THE devastation wrought by the Bhuj earthquake of January 26 has shown that there is an urgent need for creating greater awareness about earthquakes and to impart training for better preparedness to meet disaster situations, so that loss of human lives is reduced to the bare minimum.

Disaster preparedness entails detailed planning for prompt and efficient response once an earthquake strikes. It is concerned with operational planning, education and training of the population as to how to face the situation arising in the post-disaster stage.

The training at the community or individual level should focus on the various skills and drills considered essential in a disaster situation, and for this purpose programmes should be organised regularly at the local level.

The joint programmes should be aimed at developing mutual understanding and confidence, so that people learn to operate together, to delegate and accept changed roles. This is the level where one really needs imaginative and instructive training. The training must follow simulation exercises to test the decision making, communication and coordination systems.

Hazards likely to be faced in each region and their impact are site-specific, so the disaster preparedness training should be limited to emergency control aspects.

When an earthquake shock is experienced, switch-off electricity and gas, if possible. In earthquake-prone areas, the people should be advised to arrange their household goods in such a fashion that it is possible to reach the exit easily even during darkness. The corridors must be kept clear of furniture, toys etc. as it would obstruct movement in darkness.

Steps be taken to attach shelves, gas cylinders, vases and flower pots to the walls and place heavy or bulky objects on the floor or on the lowest shelves.

During earthquake shock, keep calm and do not blindly rush to doors or exits. Avoid use of lifts during such a situation. Keep away from windows, mirrors, and heavy furniture. Protect yourself by staying under a lintel of an inner door on in the corner of a room or under a table or a bed.

If you happen to be in the street when an earthquake shock is experienced, walk towards an open space in a calm and composed manner. Do not run or wander round in the streets. Keep away from buildings, particularly tall, old and detached buildings, which are more prone to collapse during earthquakes. Similar phenomenon is likely in the case of electricity towers and earthen slopes.

If you happen to be driving stop the vehicle away from buildings, walls, slopes, electricity wires and stay in the vehicle.

Aftershocks

Listen to the instructions broadcast on the radio and follow them carefully. Keep away from a stream or river with low banks, because high waves may sweep the area.

Get prepared for aftershocks and keep the electricity and (piped) gas supply turned off. Do not light matches or a cigarette-lighter for smoking, as there may be some gas/fuel leaks caused by the earthquake shock. Use torch to find your way.

In case of fire, summon the fire brigade for help. If some people have been injured seriously, do not try to move them unless it is a must and call the medical rescue team.

Clean up inflammable products, which may have got spilled on the floor during the shock.

Do not rush and help in prevention of worsening of the situation for removal of injured persons. Do not touch any metal object in contact with loose electric wires or wires themselves.

Eat something as you will feel better and more capable in helping others. If your house has been damaged badly, it would be better for you to leave. Collect water containers, food and ordinary and special medicines (for persons with heart trouble, diabetes, asthma etc.).

Do not re-enter a badly damaged building or go near a damaged structure. Help in keeping streets clear for movement of rescue vehicles.


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SCIENCE QUIZ
 TESTS YOUR 1Q
BY J.P. GARG

Q1. "Even God is bound by the uncertainty principle and canít predict future." Who said this recently?

Q2. Many buildings these days are being designed in such a way that these designs involve methods of collecting, storing, distributing and controlling heat energy flow based on the natural principles of heat energy transfer. What are such buildings called in which no external source of energy like electricity is used?

Q3. Richter scale for measuring the intensity of earthquakes is in news these days. On which mathematical scale is the Richter scale based?

Q4. Indiaís only ape confined to the forests of North-East is now an endangered species due to the cutting of trees and increasing cultivation of forest land. Which is this ape?

Q5. The most abundant gas in the earthís atmosphere is nitrogen. Which is the most abundant gas in the whole universe?

Q6. SQID is a device which can detect extremely weak magnetic fields such as those produced in the human body. Thus it is used as a non-evasive diagnostic tool for detecting abnormalities of brain and heart. What is the full form of SQID?

Q7. What is the minimum energy required to eject an electron from inside a solid (especially a metal) to outside its surface called? For which effect is this energy most significant?

Q8. Minerals are natural, homogeneous and, with a few exceptions, solid and crystalline materials that form the earth and make up its rocks. Can you tell how many minerals have been identified so far?

Q9. This small animal found in damp places sticks to a naked part of the human body and sucks blood. Which is this animal that is used to reduce joint pains and also to join two ends of a completely cut finger?

Q10. The land-to-land ballistic missile Agni-II having a range of about 2200 km was test-fired successfully on January 17,2001. On which date was Agni-I test-fired successfully for the first time?

Answers:
1. Wheelchair bound British professor Stephen Hawking who was in India recently 2. Solar passive buildings 3. Logrithmic scale 4. Hoolock gibbon or white-brown gibbon 5. Hydrogen 6. Superconducting Quantum Interference Device 7. Work function; photoelectric effect 8. More than 3,000 9. Leech 10. May 22, 1989.

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