SCIENCE TRIBUNE Thursday, May 8, 2003, Chandigarh, India
 


Genetic counselling
Rajeev Goel
T
he blossoming of the scientific revolution in the field of human genetics has led to the development of interest in genetic disorders by both scientists and physicians alike. A genetic disorder results from the change in the inherited genetic material i.e. the genes in an individualís cells.

Biological clock in plants
P
lants appear still and silent, but inside a clock is ticking. Scientists in Israel and the US Agriculture Department have discovered that plants, like animals, have a 24-hour biological clock.

Cyber warfare
Deepak Bagai
M
odern society and economy are critically dependent on computer communication links. It has become difficult to draw a line between war and peace. The information revolution has transformed the warfare methodology. History reveals that military methods have undergone changes from time to time.

UNDERSTANDING THE UNIVERSE
WITH PROF YASH PAL
Is there any funda of white holes?
I have put in the above question as received. Till three years ago I did not know the meaning of the word funda. 

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Genetic counselling
Rajeev Goel

The blossoming of the scientific revolution in the field of human genetics has led to the development of interest in genetic disorders by both scientists and physicians alike. A genetic disorder results from the change in the inherited genetic material i.e. the genes in an individualís cells. A few of the genetic disorders are hemophilia, thalassemia, Duchenne Muscular Dystrophy (DMD), phenylketonuria, Huntingtonís disease, cystic fibrosis, neural tube defects, Down syndrome and other chromosomal abnormalities. These genetic disorders can be detected by carrying out tests like amniocentesis, chorionic villus sampling, triple test, ultrasound, fetoscopy etc.

Ordering these tests is one aspect of genetic counselling which is a process of assessing family history and medical records to look for genetic disorders, suggesting genetic tests, analysing the results of the investigations and then discussing pros and cons of the results with the individuals and helping them to reach decisions as to what to do next. Genetic counselling thus is a process of communication, which addresses concerns relating to the development, transmission and prognosis of a genetic disorder. Genetic counselling is non-directive i.e. the counsellor will only inform the various options available for prevention to an individual and will never take a decision for the person seeking counselling. A good genetic counsellor uses the specially designed charts and diagrams to explain the nature and implications of genetic disorder

Genetic counselling services came into existence around five decades ago in the western countries where the genetic disorders are responsible for significant morbidity and mortality. In developing countries like India, this speciality is not yet very well developed but many people now do opt for genetic counselling especially concerning reproductive events and infertility and disorders like mental retardation, thalassemia, Down syndrome, DMD and congenital abnormalities.

A particular genetic disorder may occur in more than one member of a family. This is called a familial disorder e.g. haemophilia. However, a disorder may come up unexpectedly without previous history in the family because of a new mutation occurring at the time of conception or the development of a fetus. A genetic disorder being hereditary in nature does not restrict itself to the affected person but may pass on to the subsequent generations. The genetic disorders therefore pose continuing burden on a society. Counselling to individuals can really help in reducing the burden, especially when a promising, satisfactory and cheap therapy for most of the genetic disorders is not available.

The best time to seek genetic counselling is, therefore, before becoming pregnant so that the counsellor can assess the risk factors involved in transmission of a particular disorder. But the genetic counsellor can still be of help to you even if you are already pregnant. He or she may order certain pre-natal tests to rule out the genetic abnormalities. This does not mean that genetic counselling is required by all individuals or couples planning either a pregnancy or are expecting.

One should consider genetic counselling only if there is either a family history of genetic disorders or physical defects at birth such as spina bifida, cleft lip or palate, club foot, congenital heart defects etc. Genetic counselling is also required in cases where prenatal screening tests such as alpha-fetoprotein present abnormal results.

The mother-to-be should also meet a counsellor if she had a previous history of two or more miscarriages or babies that died during infancy. Not only this, women aged 35 years and above who are either pregnant or planning a pregnancy should also visit a genetic counsellor. With the increase in age, chances of having a child with Down syndrome increase. Pregnant women who are concerned about the effects of teratogens i.e. exposure to radiations, chemicals and pesticides, drugs and medications, viral infections and certain occupational hazards must also consult a genetic counsellor.

Couples of the interfamily marriages i.e. consanguineous marriages, should also see a genetic counsellor before they plan their family. It has been scientifically observed that there is an increased incidence of congenital structural abnormalities among the offspring of consanguineous marriages. Persons belonging to specific racial/ethnic groups or geographic areas with a certain genetic disorder most commonly found in their group or area should also opt for genetic counselling.

Genetic counselling can prove very useful to the carriers of a certain trait/disorder. Carriers are the persons who have a genetic anomaly, which is not affecting them (asymptomatic) but may affect their offspring. A genetic counsellor in the carriers can assess the probability associated with the transmission of that trait to the offspring. Genetic counselling is also very useful in case of genetic disorders of adult onset e.g. myotonic dystrophy, spino-cerebellar ataxias, Huntingtonís disease that manifest at the age of 35 years and beyond. An individual remains asymptomatic till the disease ensues. The children of such patients can be tested for whether or not they have the mutant gene responsible for the disorder. And if yes, they can be counselled for genetic testing in future pregnancy so as to have normal children.

Genetic counselling in the west is provided exclusively by genetic counsellors who are mostly health professionals having either a graduate or a postgraduate degree in medical genetics and counselling skills. However, it is unfortunate that in India, counselling is hardly a well-developed field. Counselling most of the time here is part of the consultation with a family doctor. But there are institutions like AIIMS (N. Delhi), SGPGI (Lucknow), Sir Ganga Ram Hospital (N. Delhi), PGIMER (Chandigarh), GNDU (Amritsar) etc. where the human/clinical genetics divisions or labs are well developed and can provide tests and effective genetic counselling.

The speciality of genetic counselling is very well advanced in the west. It is not only due to the increased incidence of genetic disorders in western population but also because the abortion of an affected child is more acceptable in their society especially in cases where proper therapy for a particular genetic disorder is not available. This is not the case in India where many socio-ethical questions and dilemmas come in. Many of us being fatalists accept genetic anomalies as a fate destined by God. The situation is further worsened by the dearth of medical geneticists in most of the hospitals and institutions across the country.

It is high time we reaped the benefits of the scientific advancements happening in the field of clinical genetics so as to reduce the rate of incidence of the genetic disorders. Heightened public awareness, conducting short training programmes in medical genetics for the serving doctors both in government and private sectors, setting up clinical genetics labs and running graduate or PG programme in medical genetics in medical colleges and universities will definitely go a long way in reducing the burden of genetic disorders. Last but not the least, do not forget to talk to your doctor or a medical geneticist if available, in case you have any one of the known risk factors discussed in this write-up.

The writer is from Government Medical College and Hospital, Kangra at Tanda (HP).
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Biological clock in plants

Plants appear still and silent, but inside a clock is ticking.

Scientists in Israel and the US Agriculture Department have discovered that plants, like animals, have a 24-hour biological clock.

Like the body clock that tells humans to wake up, plants have one that tells them to prepare for the sun.

The plant clock is set so it goes off around the same time every morning, usually just a few hours before noon. The late morning alarm tells plants to prepare for intense sunlight, triggering processes that help the plants make food, says Autar K Mattoo, a plant physiologist in the departmentís Agricultural Research Services lab.

The clock controls an enzyme that modifies a protein called D1, Mattoo says. This protein is critical for photosynthesis, the process whereby plants extract light and convert it to food.

When D1 binds with phosphorus, it creates a modified protein found in chloroplast - a special structure in the cell thatís made of carbohydrates, fat and proteins. Mattoo says scientists believe the modified protein tells the plant to adjust its metabolism so it will protect itself from high light.

"It cannot run away. Their roots are stuck in the soil, so they have devised and perfected processes that allow them to survive in the harshest extreme environments," he says.

If the plants are exposed to excessive ultraviolet radiation, "plants produce molecules called flavonoids, which act as the sunscreen," Mattoo says. AP
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Cyber warfare
Deepak Bagai

Modern society and economy are critically dependent on computer communication links. It has become difficult to draw a line between war and peace. The information revolution has transformed the warfare methodology. History reveals that military methods have undergone changes from time to time. Industrialisation was the keyword in World War I and mechanised tanks entered the scene in World War II. The Information revolution has resulted in a major shift as the whole world has been reduced to a global village. Cyber information crosses borders and has redefined office boundaries and responsibilities.

Cyberwar involves military operations inline with information technology principles. It includes economic, social, political and military warfare. With the advancement of computer technology, military planners perceive cyber war as both a target and a weapon. Cyber strategies are being designed to counter enemyís command and control structure, logistics, transportation and other critical missions. They are the key force multipliers. Cyberwar will be directed to target enemy countryís critical national infrastructure, emergency services and the information infrastructure itself.

Attacks against financial infrastructure will affect the business. Cyber war may also involve electronically blinding, jamming, deceiving overloading and intruding into enemyís information and communication network.

Cyberwar methods will lead to redefining the military doctrines. It is the 21st centuryís biggest innovation in warfare. This will enable the countries to have intelligent control to deceive the enemy before he does the same to you. Information technology advancements have altered the modern battlefields and eroded the hierarchies in armed forces. Preventive measures are not easy to implement in the cyberworld and the attack favours the aggressor. Defence planning needs to include the virtual cyber world. Cyber warfare in the form of virtual attacks can have consequences that are critical and far-reaching.
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UNDERSTANDING THE UNIVERSE
WITH PROF YASH PAL

Is there any funda of white holes?

I have put in the above question as received. Till three years ago I did not know the meaning of the word funda. There was no such word in any dictionary. Finally I had to ask some young students. They were amazed at my ignorance. When they started talking of fundamentals of physics and chemistry, I realised that funda is a short for fundamental, implying basic laws, even scientific reasons. So here is the "funda" behind the concept of white holes. Before we talk of white holes which probably do not exist, it might be useful to recount the science that led to the prediction of black holes.

Following the theory of gravity, particularly Einsteinís theory of relativity, it is easy to extrapolate that if the mass is large enough and the distance from the centre of that mass small enough then even light will not be able to escape from with that mass. The mass will then become invisible to the outside world. In principle a black hole can have a very small mass if the radius within which it is confined is also very small. One normally speaks of astronomical black holes that are produced through evolution and collapse of massive stars.

This could be the ultimate fate of most stars that have a mass several times the mass of the sun. Such stars collapse after the energy generating fuel inside is exhausted. Even the Pauli exclusion forces, or the degeneracy pressure, of electrons or nucleons cannot resist their inward gravitational force. In laymanís language, the structural strengths of atoms and nuclei fail under the assault of the overwhelming gravitational pressure. Such black holes have been discovered through their gravitational effect on an accompanying star in a binary system or on many stars orbiting a location that is otherwise invisible. If one finds that the required mass of the object providing the gravitational forces is higher than several solar masses we come to the conclusion that it must be a black hole. We do not see anything of what is happening inside the invisible object but we can infer its existence from what its presence does to the outside. Black holes have been found amongst separated star systems and also in the centers of galaxies, including our own.

Black holes were predicted much before they were actually observed ó or inferred. Equations of relativity, like Newtonís equations, are equally valid if the direction of time is changed. Equations that predict the formation of a black hole could be arbitrarily changed to move backwards if we change the direction of time. Then we could make a theory in which a hole, instead of sucking in every thing, including light, within itself, would spew things out. While a black hole does not allow exit, such a hole would bar entry. Therefore we could be calling it a white hole. There is not much more to this story. Incidentally you would be able to think of creating a white hole only if you can also destroy a black hole! Both these acts require time reversal.

Why do we not find any straight-lined features in the natural state of the universe ó anywhere in the universe?

This is an interesting observation. Yet I could pick an argument with you. You have to define two things. How long should the line be to be qualified as a line? If you would allow me to look at the microscopic universe I could point towards a myriad of crystals. They arrange themselves in planes and rows of atoms that are pretty straight. In geology you encounter a large number of lineaments and faults that extend over hundreds and thousands of kilometres.

Perhaps you would allow me to assume that whenever I have a flat plane it is but a translation of a straight line. Our world is full of marble and sandstone slabs that are pretty plane. I know that they must have some curvature due to the fact that they were originally laid out as slabs of sediment on the surface of the earth and therefore have to incorporate the curvature of the earth! Having said all this we should be grateful that the universe has made use of a variety of shapes in abundance, even though the patterns seem to be repeated in many forms. If you are interested in identifying morphological forms on other celestial bodies that would indicate a non-natural or human artifact, there might be several choices. The astronauts who first went to the moon said that the only human structure they could discern on the earth was the Great Wall of China. That is not very straight, though. Our highways and railway lines might not be visible from that far but would show up. I am mentioning all this to give tangential support to your observation ó it is easy to identify linear features on earth using remote sensing satellites.
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A soggy secret of El Ni`F1o

NASA-funded researchers have discovered El Ni`F1oís soggy secret. When scientists identified rain patterns in the Pacific Ocean, they discovered the secret of how El Ni`F1o moves rainfall around the globe during the life of these periodic climate events when waters warm in the eastern Pacific Ocean.

The results may help scientists improve rainfall forecasts around the globe during the life of an El Ni`F1o, and may also offer new insights into how an El Ni`F1o develops.

The findings were highlighted in a paper authored by Scott Curtis of the University of Maryland - Baltimore County, Baltimore, Md., and Bob Adler, of Goddard Space Flight Center, Greenbelt, Md. The study appeared in a recent issue of the American Geophysical Unionís Journal of Geophysical Research.

In an effort to predict and understand the effects of El Ni`F1o, most scientists focus on seasonal changes in rainfall patterns, like where and when rain falls during winter. This study takes a different approach by first looking at the evolution of rainfall over the geographic area of the Pacific, which has the power to change the global winds and re-direct rainfall patterns around the world.

Curtis and Adler found a significant pattern of alternating rainfall for El Ni`F1os since 1979, with wetness in eastern China, dryness over Indonesia and wetness in the south Indian Ocean and Australia.

Fossilised fish as thermometer

Fossilised fish bones may help scientists to reconstruct the temperatures of 65 million years ago, according to a paper in Nature, co-authored by colleagues representing three generations of researchers.

St. Lawrence University alumnus Scott J. Carpenter of the University of Iowa, Iowa City; Chapin Professor of Geology J. Mark Erickson, St. Lawrence University, Canton, NY; and F.D. "Bud" Holland Jr., professor emeritus, department of geology and geological engineering, University of North Dakota, Grand Forks, ND, co-authored the paper, which compared the carbon, oxygen and strontium isotope ratios of four fossils collected from the Fox Hills Formation of South Dakota. The relics were the calcium carbonate ear stones belonging to Vorhisia vulpes, a Late Cretaceous fish that spawned in brackish water before migrating to open marine waters of the Western Interior Seaway of North America.
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