Features
LOVEABLE BUT LETHAL: When four-legged stars remind us of a silent killer
From Aloka the Peace Dog to Manula the School Icon — Sri Lanka’s love for dogs is wholesome and beautiful. But, behind every wagging tail lurks a public health crisis that kills silently, swiftly, and without mercy.
Aloka and Manula: Stars with a Message
Sri Lanka fell in love, not once, but twice in the span of a few weeks. First came Aloka, the serene, soulful dog who walked alongside venerable Buddhist monks during their peace walk in the USA, matching their calm stride with a dignity that moved the nation to tears. By nightfall, Aloka was not just a Sri Lankan celebrity he was an international sensation, a symbol of compassion and coexistence that transcended borders. The world watched, and the world smiled.
Then came Manula. from the schoolyard of Tissa Vidyalaya, in the Kalutara district. A photograph went viral – a scruffy, joyful dog apparently “performing” alongside students at the school’s annual inter-house sports meet band performance. Manula, a school mascot born not by appointment but by the daily love of students and teachers, became an overnight hero.
Both dogs share something beyond their celebrity. Both are native breeds, the ancient indigenous dogs of India and Sri Lanka, lean and hardy, shaped by centuries of co-evolution with humans on this subcontinent. Both roam freely. Both are adored. And both, unknowingly, sit at the centre of a public health conversation that Sri Lanka urgently needs to have.
When Aloka walked among the crowds, children rushed forward, small hands reaching out, eager to touch this gentle, famous dog. Manula, it is safe to assume, is petted by dozens of schoolchildren every single day. These are acts of love instinctive, natural, beautifully human. But they are also, without the right precautions, potentially dangerous.
The disease these encounters could transmit is rabies. And, in Sri Lanka, rabies is not a distant theoretical threat. It is the country’s number one public health emergency one that kills, maims, and drains the economy, all while remaining almost entirely preventable.
What is Rabies? Understanding the Invisible Enemy
Rabies is a viral disease caused by the Rabies lyssavirus, a member of the Rhabdoviridae family. It is one of the oldest known infectious diseases in human history, described in ancient Mesopotamian texts over four thousand years ago. It is also one of the most terrifying: once symptoms appear in a human being, rabies is almost universally fatal. The mortality rate after symptom onset approaches 100%.
The virus attacks the central nervous system the brain and spinal cord causing progressive and irreversible neurological deterioration. There are two clinical forms. Furious rabies, the more common form, produces the haunting symptoms most people associate with the disease: extreme agitation, hydrophobia (an irrational, violent terror of water), aerophobia (fear of air currents), hallucinations, excessive salivation, and aggressive behaviour. Paralytic rabies, sometimes called “dumb rabies,” progresses more quietly with gradual muscle paralysis, weakness, and eventual coma and is often misdiagnosed.
Death typically follows within two to 10 days of the onset of symptoms, caused by respiratory failure or cardiac arrest. There is no cure once the virus reaches the brain.
How Rabies Travels from Dog to Human
The transmission route is straightforward but sobering. The rabies virus lives in the saliva of infected animals. It enters the human body through a bite, or when infectious saliva contacts broken skin, a scratch, or mucous membranes such as the eyes, nose, or mouth. A lick from an infected dog on an open wound or a child’s eyes can, in rare cases, be sufficient.
Once inside the body, the virus travels along nerve fibres towards the brain at a rate of approximately 12 to 24 millimetres per day. This journey, called the incubation period, is deceptively long. It typically ranges from one to three months, though it can be as short as a week or as long as a year, depending on the site of the bite (bites closer to the head are more dangerous), the severity of the wound, and the viral load introduced.
This long incubation period is simultaneously a tragedy and an opportunity. It is a tragedy because people often forget about or dismiss a dog bite weeks later, believing they are safe. It is an opportunity because there is a window, a precious, life-saving window during which post-exposure prophylaxis (PEP), a series of rabies vaccinations, can prevent the virus from reaching the brain and save the patient’s life with near-complete certainty.
What To Do Immediately If a Dog Bites You
Every second matters. The following steps must be followed without hesitation:
Step 1 — Wash the wound immediately and thoroughly.
This is the single most important first-aid measure. Wash the bite site vigorously with soap and running water for a minimum of 15 minutes. The mechanical action of washing physically removes viral particles. Research shows that thorough wound washing alone reduces the risk of rabies transmission by up to 50%. Do not panic. Wash, wash and wash.
Step 2 — Apply an antiseptic.
After washing, apply povidone-iodine, ethanol, or another virucidal antiseptic to the wound if available. Do not cover the wound tightly and allow it to breathe.
Step 3 — Go to hospital or a rabies clinic immediately.
Do not wait. Do not adopt a “wait and see” approach. Do not be reassured by the dog appearing healthy as healthy animals can shed the rabies virus before showing symptoms. Present yourself to the nearest government hospital or Anti-Rabies Clinic (ARC). Sri Lanka has a nationwide network of these clinics.
Step 4 — Begin Post-Exposure Prophylaxis (PEP).
A doctor will assess the category of exposure and recommend the appropriate PEP regimen. This typically involves a course of intramuscular rabies vaccines administered over 14 to 28 days. For severe bites (Category III), Rabies Immunoglobulin (RIG) will also be injected into the wound site to provide immediate passive immunity. PEP is safe, effective, and free of charge at government hospitals in Sri Lanka.
Step 5 — Complete the full vaccine course.
This is where many patients fail. The vaccines work only if the complete schedule is followed. Missing doses can leave a person unprotected. PEP must be completed, regardless of whether the dog is found, tested, or appears healthy afterward.
One critical caution: if you are bitten on the face, head, neck, or hands areas with rich nerve supply close to the brain treat this as the highest emergency and reach a hospital as fast as humanly possible.
Rabies in the World: A Disease That Refuses to Disappear
Despite being entirely vaccine-preventable, rabies remains a significant global public health challenge, responsible for an estimated 59,000 human deaths annually, according to the World Health Organisation (WHO). This figure is almost certainly an undercount; many deaths in rural areas of Africa and Asia go unreported or are misattributed. The WHO estimates that 99% of human rabies cases are caused by dog bites.
Africa and Asia bear the overwhelming burden of the disease, together accounting for approximately 95% of all global rabies deaths. The countries worst affected include India which alone accounts for roughly 36% of global rabies deaths, with an estimated 18,000 to 20,000 fatalities per year along with Bangladesh, Ethiopia, China, and the Philippines. Shockingly, children, under 15 years of age, account for up to 40% of all rabies victims, largely because they are more likely to engage with stray dogs and and are less likely to report bites.
The economic cost of rabies, globally, is staggering. A 2015 study published in PLOS Neglected Tropical Diseases estimated the annual global cost of rabies, including lost lives, healthcare expenditure, and livestock deaths, at over USD 8.6 billion.
The encouraging news is that rabies can be eliminated. Several countries, including Japan, the United Kingdom, Australia, and most of Western Europe, are certified rabies-free, having achieved this through sustained dog vaccination campaigns, stray dog management, and public education. The WHO, together with the World Organisation for Animal Health (WOAH) and the Food and Agriculture Organisation (FAO), has set the ambitious target of zero human deaths from dog-mediated rabies, globally, by 2030.
South Asia: A Region Under Threat
South Asia represents one of the world’s most severe rabies hotspots. India’s enormous burden has already been noted. Bangladesh has made significant progress in recent years through mass dog vaccination, reducing human rabies deaths substantially. Nepal continues to struggle with high exposure rates, particularly in rural areas. Bhutan has made commendable strides with its dog vaccination programme.
Sri Lanka stands at a critical juncture. While the country has reduced its annual rabies death toll, significantly, over the decades, from hundreds of deaths per year, in the 1970s and 1980s, to the current figures of approximately 20 to 40 deaths per year, this progress masks a troubling reality: the disease has not been eliminated. And every death from rabies is entirely preventable.
Sri Lanka’s Rabies Crisis: Dogs, Schools, and a Cultural Paradox
Sri Lanka’s relationship with dogs is ancient and complex. In Buddhist tradition the faith of the majority of Sri Lankans compassion extends to all living beings. Feeding stray animals is considered an act of merit (pin). Harming an animal is considered morally reprehensible. This cultural and religious fabric has, over centuries, created a society extraordinarily generous to stray dogs and, unintentionally, a society extraordinarily vulnerable to the diseases they carry.
Across Sri Lanka, from Colombo’s busy urban streets to the most remote village in the deep south or the far north, stray dogs are everywhere. They sleep in temple grounds. They loiter near marketplaces. They gather at rubbish dumps. And they congregate in numbers that would astonish any visitor — at school gates, school canteens, and school playgrounds.
The school dog phenomenon is perhaps the most acute expression of Sri Lanka’s rabies vulnerability. Across the country, virtually every school, urban or rural, large or small, has its unofficial resident pack of stray dogs. These animals are fed daily by students sharing their lunch, by teachers, and by school staff. They become familiar, named, beloved – like Manula. And because they are beloved and familiar, children touch them, play with them, hug them, and allow the dogs to lick their faces, all without any thought of risk.
This is not carelessness. This is kindness, rooted in culture and religion. But it is kindness, without knowledge, and that gap between compassion and information is where rabies lives and kills.
The Economic and Social Toll of Rabies in Sri Lanka
The cost of rabies in Sri Lanka is far greater than the death toll alone suggests. It exacts a profound economic and social price that touches families, the healthcare system, and the broader economy.
Each year, Sri Lanka’s Anti-Rabies Clinics manage an estimated 100,000 to 150,000 dog bite cases. The provision of Post-Exposure Prophylaxis vaccines and immunoglobulin for these patients imposes a massive and recurring burden on the public health budget. The cost of a single PEP course, if purchased privately, runs into tens of thousands of rupees. Multiply this across over a hundred thousand patients annually, and the numbers become daunting.
Beyond direct medical costs, there is the cost of lost productivity. Dog bite patients require multiple hospital visits for vaccine doses. Working adults lose workdays. Farmers and labourers in rural areas, often the most vulnerable to dog bites, face income losses that can devastate already fragile household economies. Children bitten during the school day lose schooling time and, in some cases, develop lasting psychological trauma and cynophobia (fear of dogs).
Then there is the immeasurable social cost: a rabies death in a family is uniquely devastating. It strikes with grotesque swiftness once symptoms appear. Families watch helplessly as a loved one, often a child, deteriorates into terror, agony, and death within days. The psychological scars endure for generations. And the cruel irony is that this death, had the family sought treatment promptly, was entirely and easily preventable.
Protecting Yourself: How to Avoid Dog Bites
Awareness and behavioural change are the first and most important shields against rabies. The following practices, especially when taught to children, can dramatically reduce the risk of dog bites:
Never approach a dog that is eating, sleeping, or caring for puppies. These are the moments when even gentle dogs are most likely to bite defensively. Never run towards or away from a stray dog — sudden movements trigger the chase instinct. Stand still, avoid eye contact, and back away slowly if a dog approaches aggressively.
Never attempt to pet a dog through a fence or gate. Never reach into a dog’s sleeping space. Do not disturb a dog that appears ill or injured without professional assistance. A sick dog is an unpredictable dog.
Teach children at home and at school that while loving animals is wonderful, there is a safe way to do so. Children must understand that they should always ask an adult before approaching an unfamiliar dog, and should never put their faces close to a dog’s face, however friendly the animal appears.
Good Practices When Petting a Dog with an Unknown History
For a dog like Aloka or Manula – a dog beloved by many but with an unknown vaccination history – some simple, common-sense practices can significantly reduce your risk:
Always let the dog come to you rather than approaching it forcefully. Extend the back of your hand slowly, at the dog’s nose level, and allow the dog to sniff and initiate contact. If the dog turns away or shows signs of discomfort ears flattened, tail tucked, growling does not persist.
Pet the dog on the sides of the neck, chest, or back. Avoid the top of the head, initially, and never reach over a dog’s head with a stranger this can feel threatening to the animal. Do not allow a stray dog to lick your face, lips, eyes, or any open wound or sore. After touching any stray or unfamiliar dog, wash your hands thoroughly with soap and water before touching your face or food.
If you have children with you, maintain physical supervision at all times. A child’s instinct is to rush forward, kneel down, and hug a dog all of which can be risky with an animal of unknown temperament and health. Channel the child’s love into safe, supervised interaction.
Being a Responsible Dog Owner in Sri Lanka
If you have a dog at home or if you are considering getting one, responsible pet ownership is not just an ethical commitment to your animal. It is a public health responsibility. Here is what every Sri Lankan dog owner must do:
Vaccinate against rabies every year, without exception.
A single dose of rabies vaccine for your dog costs a fraction of the cost of a human PEP course. Your vaccinated dog cannot transmit rabies. Vaccination is available at government veterinary offices island-wide, often at minimal or no cost during mass vaccination campaigns. There is no excuse to leave your dog unvaccinated.
Register your pet.
Dog registration with your local municipal or pradeshiya sabha authority is a legal requirement in Sri Lanka. Registration facilitates rabies vaccination tracking and helps authorities manage stray dog populations.
Sterilise your dog.
Population control is central to rabies elimination. Sterilised dogs do not reproduce, reducing the number of unowned, unvaccinated puppies on the street. Many government and NGO programmes offer low-cost or free sterilisation services.
Do not allow your dog to roam freely.
A dog that roams unsupervised can be bitten by other animals, exposed to rabies in the environment, and can itself bite others. Leashing and containing your dog within a secure space is a basic responsibility of ownership.
Monitor your dog’s health.
Know your dog. Watch for changes in behaviour, like sudden aggression, disorientation, excessive salivation, difficulty swallowing, or aversion to water and light. These can be early signs of rabies. If you suspect your dog has been bitten by an animal of unknown rabies status, contact a veterinarian immediately.
Educate your household and neighbours.
Share information about rabies, wound washing, and the importance of seeking medical attention after dog bites. In Sri Lanka, a significant proportion of dog bite victims, particularly in rural areas, do not seek treatment because they are unaware of the risk or fear stigma. Education saves lives.
Love Your Dog. Protect Your Community.
Aloka and Manula represent something genuine and beautiful about Sri Lankan character, a capacity for compassion, a willingness to extend kindness to creatures beyond our species, a recognition that every living being deserves love. These are not values to be abandoned. They are values to be celebrated, protected and informed.
The goal is not to make Sri Lankans fear dogs. The goal is to make Sri Lankans safer in the love they already give so freely. Wash your hands after petting a stray. Vaccinate your dog. Teach your children. Seek treatment immediately after a bite. These are small acts with life-saving consequences.
Aloka walked in peace. Manula played in joy. May every dog in Sri Lanka, stray or owned, campus icon or temple companion live in a country where they are loved safely, vaccinated consistently, and managed with the compassion and the wisdom that Sri Lanka’s great religious and cultural traditions have always, at their best, demanded.
And may every child who reaches out to touch a dog do so knowing they are safe because adults around them have done their duty.
by Dr. Niroshan Gamage
Director – Public Health Veterinary Services, Ministry of Health
Features
‘A remarkable time capsule’: The enchanting history of Oxford University’s 750-year-old medieval library
Predating the Aztec Empire, Merton College Library in Oxford has been used by everyone from celebrated 14th-Century mathematicians to JRR Tolkien. In an exclusive interview with the BBC for its 750th birthday, its librarian describes what makes it so special.
At Merton College in Oxford, there is an antique chest. In the Middle Ages, three key-holders had to be summoned to reveal the riches within. But this treasure wasn’t gold or jewels. It was books.
Such strict security may sound overly cautious for mere parchment. But in an era before the printing press, books were a valuable commodity. They could take months to produce, as the entire text had to be painstakingly written out by hand. So, just as universities solicit cash from their alumni today, Merton College insisted its 13th-Century fellows donated books.
“There’s no single definition of a library” – Prof Teresa Webber
The Archbishop of Canterbury issued a decree in 1276 introducing this requirement, which marked the beginning of the library at Merton College. It has been running continuously ever since. To put that length of time in context, Merton’s library predates the Aztec Empire. Its unbroken history stretches from before the Black Death to beyond the Covid-19 pandemic. And its users have encompassed everyone from famous 14th Century mathematicians to Lord of the Rings author JRR Tolkien.
This month marks the library’s 750th anniversary. It’s a major milestone. But Merton’s extraordinary lifespan has been recognised since the Victoria era, when it was routinely described as the oldest library in England.
In the 20th Century, writers like Rudyard Kipling and John Buchan referenced it in works of historical fiction, bolstering its reputation as a particularly venerable library. As the cultural recognition of “the famous Merton Library” grew, claims about its longevity became exaggerated. Some overzealous Oxonians even declared it the oldest library in the world.
The origins of the historic library
Historians today are more careful about making such bold declarations. “It’s a complicated question,” says Prof Teresa Webber from the University of Cambridge. “There’s no single definition of a library. And there were all sorts of stages in the development of what we think of today as a library.”

The origins of the library at Merton are certainly different from how we think of such institutions now. There was no librarian and there were no shelves for browsing. “There was a system of loaning and returning books from the chest,” Merton’s librarian, Dr Julia Walworth tells the BBC. “It would have been a formal thing. Rather than just saying, ‘Oh, go rummage and find the books you need,’ the whole community would come together to open the chest.”
“Horizontal shelves were installed for placing books upright. Merton is the first recorded use in Britain of this method of storing books” – Dr Julia Walworth
Merton’s collection started evolving into a modern library quite quickly. Just a few years after the Archbishop’s decree, several books were stored outside the chest for the first time. They were chained to a table in the college, making them available at any time. According to Walworth, this innovation “anticipates the modern distinction between loan and reference library collections”.
Merton’s book treasury moved closer to becoming a modern library in the 1370s, when a purpose-built room was constructed to house the growing collection. It was here that Merton introduced a vital improvement in book storage. “Horizontal shelves were installed for placing books upright,” Walworth says. “Merton is the first recorded use in Britain of this method of storing books.”
Curiously, Merton’s books were shelved with their spines inwards and their titles inked on the paper facing out. This was due to the continued use of chains, which were clipped on the fore-edge of each book’s cover. “The fellows were aware that chained books had a better chance of survival than books that went out on loan,” Walworth explains.

Today, just a few volumes in the library are chained – purely for display purposes. And the remaining books are now placed in the modern fashion with their spines out. But otherwise, the medieval room remains a remarkable time capsule of the library’s history. Near the entrance, visitors can even see the 13th-Century chest, which Walworth believes is the original. During term time, the historic library room is still used by students. And this ongoing use is a major factor in the superlatives that are often applied to the age of Merton’s library. “It’s hard to think of an earlier library room that’s been in continuous use,” Webber says.
Claims about Merton’s longevity first gained traction in the Victorian era, as it became more of a tourist destination. Visitors would marvel at its stained-glass windows, as well as rare books like its 15th-Century edition of The Canterbury Tales. “It’s one of the earliest books printed in England,” Walworth explains. “What’s unique about Merton’s copy is the hand-illuminated borders.” Among those who visited the library was American writer Ralph Waldo Emerson, who mentioned it in his 1856 travelogue English Traits. In 1884, a young Beatrix Potter visited, describing the library’s “beautiful oak roof” and “ancient, dusty smell” in her diary.
By this time, books and magazines were increasingly describing the library in record-breaking terms. An 1878 guide to Oxford called Merton’s library “the most ancient now in England”. The 1885 edition of the Encyclopaedia Britannica described it as “the oldest existing library in England”. Gradually, these claims were inflated. A 1928 article in The Times recounted an event held by the Oxford Preservation Trust in which it was declared “the oldest library in the world”.

This growing perception of Merton’s longevity was even referenced in F Scott Fitzgerald’s classic novel The Great Gatsby. In the book, the multi-millionaire title character fills his mansion with imitations of history’s most prestigious rooms. So, it’s only natural that his books live in a recreation he refers to as “the Merton College Library”. As Walworth puts it, “Merton’s library had become a byword for the ‘best’ ancient library” by that time. She even points out that Fitzgerald’s fictional scenario had roots in reality. “The dining clubs at Princeton University have historical imitation rooms. One of them is based on the Merton College Library.”
But today, Walworth rebukes any suggestion that Merton’s library is the world’s oldest. She prefers to describe it with several qualifiers, calling it “one of the oldest still-functioning academic libraries in Europe”. That more measured description recognises that not all historic libraries can be categorised in the same bucket – monastic libraries functioned very differently from private subscription libraries, for instance. But it also acknowledges ancient institutions around the globe. “It’s not that people weren’t aware of other parts of the world in the past,” Walworth says. “But there was a tendency for people to think of their own world as having primacy. Our outlook tends to be more global now, quite rightly.”
The debate over the world’s oldest library
Among these global institutions, there are several candidates for the contested title of world’s oldest library. When the Al-Qarawiyyin library in Morocco underwent a major restoration in 2016, it was described by several media outlets as “the oldest library in the world”. But Guinness World Records cites Saint Catherine’s Monastery in Egypt as the oldest continuously operating library.

In both cases, it’s difficult to establish an exact starting date. For the Al-Qarawiyyin library, some scholars have cast doubt on the library’s claims of Ninth-Century origins, saying the “story has much myth about it”. In the case of Saint Catherine’s Monastery, the building was constructed in the Sixth Century. But ancient writings suggest that the library’s collections could date from two centuries earlier. “It depends how you count it,” Walworth says. “When are you going to start the timeline? What is the beginning of a library?”
However, Prof Richard Gameson from Durham University tells the BBC that the library at Saint Catherine’s Monastery “is probably the one with the longest continuous history”. But he caveats this by adding that “the nature of the ‘library’, how it was used and how it was understood changed over time”. So, any claim to be “the oldest” needs to be accompanied by an appropriate explanation of what a library is. Finding a single definition that allows for one conclusive record-holder seems a near-impossible task.
“You can think of the oldest library as the oldest coherent collection of books that stayed together,” says Webber. “Or you can think of it in terms of the survival of the physical space. Or you could ask, ‘What’s the oldest space and collection of books which has been there continuously?'”
She offers the Dunhuang Library Cave in China as an example. This secret chamber was filled with manuscripts and sealed sometime around the 11th Century. It was only opened again after its rediscovery in 1900. “But the books were still in continuous storage there,” Webber says.

Finding a common definition of a library will only become more challenging now, as digital institutions offer physical spaces that do not even contain any books. “The definition of what a library is has always needed to be a capacious one,” says Webber. “The introduction of new technology is simply a continuation of that. But I don’t think the library as a physical space will disappear.”
Walworth is similarly optimistic, as she embarks on a project to digitise Merton’s manuscripts. “People will be able to access them anywhere. But I think they will still want to come and see the library and understand how people used books in the past.”
Reflecting on the 750-year span of Merton’s library, this digital phase seems like just another step in a long evolution. Just as the books moved from the Archbishop’s chest to chained desks to horizontal shelves, now they will enter the virtual realm. “I suppose that’s why I now find it less useful to talk about libraries as ‘the oldest’,” Walworth says. “For me, the story is not about how long a library has been running. It’s more about the sense of community.”
She points out that the tradition of donating books introduced by the Archbishop of Canterbury in 1276 persists to this day. “What started when he laid down those injunctions was the idea of a common collection built by the people. So, it’s just remarkable that for 750 years people have maintained this connection with an institution and its books.”
Perhaps that proves that books really are the most durable treasure – whether they are handwritten on parchment and sealed in an antique chest or distributed as pixels in the cybernetic ether.
[BBC]
Features
Discovery of molecular structure of primary genetic material of life
World DNA Day falls on 25 April:
On 25 April 1953, Watson and Crick published an article, in the acclaimed journal “Nature” titled “Molecular structure of nucleic acids: A structure for deoxyribonucleic acid”.
The one-page article largely based on theoretical arguments and the previous work of Rosalind Franklin who examined DNA using X-rays, changed the world forever by explaining how genetic information is copied and transmitted.
Everyone concerned with promoting science in the country should be aware of the story behind the discovery of DNA and tell it to their children and students and remind the policymakers.
The world commemorates the transformative event on 25th April every year. An example vividly illustrates how intense curiosity and imagination, rather than mere indulgence in technologies, leads to groundbreaking discoveries.
DNA Day is also intended to celebrate the completion of the Human Genome Project in 2003. Genome means the entire set of genetic information characterising an organism.
Heredity and inheritance
Heredity is the cause of transferring traits from parents to their offspring. The closely related word “inheritance “refers to the specific nature of the transmitted trait. For example, we say intelligence is hereditary in their family and he inherited his father’s intelligence.
The resemblance of progeny to parentage was common knowledge, taken for granted and considered a blending of maternal and paternal traits. Philosophers of antiquity proposed several theories to explain the inheritance of parental traits by the offspring. Hippocrates believed the essence of all body parts of the parents are incorporated into the male and female germinal essence and therefore the offspring display characteristics as a proportionate blend. Aristotle offered a different explanation. He argued that the active principle is in the male seminal fluid and the mother’s blood provided the original body material. The inaccuracy of these theories was apparent. Sometimes children possess qualities akin to grandparents rather than parents. Fathers or mothers of humans and animals, deformed by accidents or disease, gave birth to normal children- a clear proof that the acquired characters are not inherited. Children of a blue-eyed mother and a brown-eyed father have either blue or brown eyes but not a blend of blue and brown.
Two golden sayings in our culture, “Arae gathi nare” and “Jammeta wada lokuei purrudha” (“Hereditary characters persist” and “Habits overtake heredity “), agree more with modern genetics, than the views of Hippocrates and Aristotle.
Gregor Mendal’s groundbreaking experiment
The Austrian mathematician cum botanist, Gregor Mendel was the first to conduct a systematic investigation to understand the cause of heredity. Being unconvinced of the traditional explanations, he carried out a series of experiments lasting eight years to determine how the traits (plant height, seed color, flower color etc.) of pea plants are transmitted from generation to generation. When Mendel cross pollinated tall and short plants, he found that the progeny was entirely tall. However, when first generation tall plants were allowed to self-pollinate, the missing short trait reappeared at a statistically significant probability of 25 percent. Mendel’s work provided an unequivocal proof that traits do not blend but exist as unique entities, manifested from generation to generation following a predictable mathematical pattern.
Mendel’s finding remained unrecognized for more than 30 years. His ideas were too far ahead of time and biologists were shy of mathematics. In the early 1900s several European botanists arrived at the same conclusion based on independent experiments. With the advancement of microscopy, a great deal of information about plant and animal cells was gathered. A key finding was the presence of colored bodies in the cell nucleus named chromosomes, seen separating during cell division, leading to the hypothesis that Mendel’s genetic units (genes) should be physical entities present in the chromosomes.
Chemists and biologists wondered what the genetic material in chromosomes made off. Is it a protein, carbohydrate or a lipid? Most biological materials are constituted of these substances.
Discovery of DNA
Great discoveries are made by unusual people. The Swiss Friedrich Miescher belonged to a clan of reputed physicians. Following family tradition, he qualified as a doctor but did not engage in profitable practice of medicine. He decided to do research to understand the foundations of life. In search for new biological substances, he experimented with pus deposited in bandages and extracted a substance rich in phosphates but very different from proteins. The new substance called “nuclein” was indeed DNA. Later, the German biochemist Albrecht Kossel following the Miescher’s work, showed that DNA contains four crucial compounds, adenine (A), cytosine (C), guanine (G) and thymine (T), known as nucleotide bases.
Avery – MacLeod – McCarthy Experiment
The flu pandemic of 1918 killed an estimated 50 million people worldwide due to the pneumonia that followed the viral infection. Pneumonia was caused by the virulent bacterium Streptococcus pneumoniae. The British bacteriologist, Frederick Griffith attempting to find a vaccine for pneumonia, worked with two strains of Streptococcus pneumoniae, one virulent causing pneumonia in mice, and the other avirulent to them. He found that neither the virulent strain denatured by heating nor the live avirulent strain injected into mice caused the disease, whereas a mixture of the denatured virulent strain and the live avirulent strain was deadly to mice just as the virulent one. He concluded that some chemical compound present in the virulent strain – a transforming principle – has changed the avirulent strain to the virulent strain.
In 1944, Oswald Avery, Colin MacLeod and Maclyn McCarty working at the Rockefeller University, United States, continued the work of Frederick Griffith to identify the transferring principle and found that it is not protein as widely believed, but deoxyribonucleic acid (DNA). Their result pointed to the conclusion that DNA is the carrier of genetic information.
A book by a physicist that triggered a transformation in biology
The insights of brilliant brains engaged in fundamental inquiry have opened the way for major scientific discoveries and technological innovations. In 1944, the Austrian theoretical physicist Erwin Schrodinger, one of the founders of quantum mechanics, published a book titled “What is life? The physical aspect of the living cell “. The American biologist Maurice Wilkins said he was so inspired by Schrodinger’s book and after reading it, he decided to switch from ornithology to genetics. While physicist Maurice was influenced to take up biology. Francis Crick was a physicist working on magnetic mines for the British Admiralty during the war. After reading “What is life” he thought a physicist could find treasures in biology and joined the Cavendish Laboratory in Cambridge to pursue a Ph.D.
Structure of the DNA molecule
When DNA was shown to be the molecular entity that encodes genetic information, chemists rushed to determine its structure.
The pattern formed when X-rays passing through a material cast an image on a screen, provides information about its molecular structure. In 1938, the English physicist William Astbury examined DNA using x-rays and concluded that the molecule has a helical structure. Having heard a group in the United Kingdom was attempting to unearth the structure of DNA, the American theoretical chemist, Linus Pauling, adopted Astbury’s data and proposed a model for the structure of DNA, publishing the results in the journal “Nature” in January 1953.
There was an obscure but remarkably talented person, Rosalind Franklin, pursuing x-ray diffraction studies on DNA at King’s College London. After a painstaking effort, she obtained accurate x-ray diffraction images of DNA. Her colleague, Maurice Wilkins, working in the same laboratory, passed the images to Francis Crick and James Watson at Cavendish Laboratory.
Crick and Watson were more insightful and theoretical in their approach to elucidating the structure of DNA. They, inspired by Erwin Schrodinger’s hypothesis, that the entity accounting for heredity should be an aperiodic molecular entity in cells, arrived at the double helix model, showing that Linus Pauling’s model was erroneous. The Crick – Watson model explained how DNA stores information and replicates during cell division. Their assertions were subsequently confirmed rigorously by experimentation. Crick, Watson and Wilkins received the Nobel Prize for Physiology and Medicine in 1962.
The work following the Crick – Watson model, firmly established that the DNA is a polymer string constituted of two strands made of a sugar- phosphate backbone, connected to each other by linkage nucleotide bases A, T, G, C. The base A links base T and G to C. When one strand is defined by the arrangement of bases, the complementary strand is defined. The arrangement bases store information analogously to a four-letter alphabet. Each individual in a species has a unique sequence of arrangement base pairs. The variation within the species is generally a fraction of a percent.
The Watson-Crick model also explained how the DNA molecule replicates. The two strands unwind and separate, and two complementary strands are inserted. The detailed dynamics of the replication process are not fully understood.
‘DNA is a cookbook’
DNA functions like a multiple – volume cookbook, written in a four-letter alphabet. The volumes are kept in a rack in the kitchen. The rack is the nucleus and volumes on it are the chromosomes, and the cell is the kitchen. A paragraph giving a recipe is a gene. Enzymes act as chefs, who read recipes and give instructions to cell machinery to prepare the dishes, which are proteins. The system is so complex; a complete macroscopic analogy would be impossible.
The significance of the Crick- Watson work
Until Charles Darwin proposed the idea of evolution, biology lacked a theoretical foundation. Darwin hypothesized, when organisms reproduce, the progeny inherit parental characters, but there are variations. The variants, though similar to the parents, have some new or altered characters. If these characters, originating from mutations or cross – breeding are favorable for survival in the environment, they dominate in the population, inheriting advantageous traits. Thus, random generation – to – generation, advancements of living organisms, become possible – a way of improving the design of things in a production process without a designer. Living systems store information and progeny retrieve them, when required. A bird hatched from an egg when matured, knows how to fly.
The discovery of DNA and understanding how it stores genetic information, replicates and mutates explained Darwinian evolution. A mutation is a change in the ordering of base pairs, accidentally during replication or due to external chemical or physical causes. In sexual reproduction, the offspring gets nearly half of its DNA from each parent. Consequently, the offspring does not have DNA identical to one parent. It mixes up DNA in the species. However, mutations generate new genes, driving evolution. Sexual reproduction and mutation acting in concert introduced the diversity of life on earth we see today.
Once science becomes explanatory and predictive, it opens the way for innovations. Theories of mechanics and electromagnetism formulated in the late 19th and early 20th centuries brought forth modern engineering, transforming it from an empirical craft to a scientific technological discipline. Before the discovery of DNA structure and its function, biological innovations were largely empirical. Today we have genetic engineering – genes in organisms can be manipulated. The goal of more advanced genetic engineering, referred to as synthetic biology, aims to induce major genetic changes to organisms by incorporating several genes to alter biochemical, physiological and anatomical functions. Gene technology is rapidly transforming medicine, agriculture and biotechnology. Cures have been found for diseases formerly branded incurable.
How did DNA come into existence
Life is believed to have originated in prebiotic oceans enriched with carbon and nitrogenous substances. How did DNA originate there? Today, chemists can synthesize DNA in minutes, via selective procedures, only humans can do with their knowledge. Even in a vast ocean containing trillions of times more molecular ingredients than in a test tube, a molecule as complex as DNA is most unlikely to be created by random events during the largest possible time scales of the universe. A plausible scenario would be DNA evolving from simpler self-replicating molecules such as RNA (a single strand of DNA) precursors. Unlike RNA, DNA is highly stable and good stability is necessary for the evolution of advanced forms of life.
Epigenetics
Earlier we pointed out there are two golden sayings in our culture: “Arae gathi nare” and “Jammeta wada lokuei purudha (“Hereditary characters persist” and “Habits overtake heredity “). The first is a consequence of our genetic predisposition determined by DNA and explicit genes. However, the character of an individual is also influenced by the physical, social and cultural environment. Although completely non-genetic, our children frequently follow habits we indulge in. Again, the behavior of an individual is also influenced by the physical, social and cultural environment.
The environmental factors also trigger or silence genes. The study of this important genetic effect, which does not alter the sequence of base pairs, is referred to as epigenetics. Epigenetic effects could be deleterious or beneficial. Sometimes, chronic stress causes disease, including cancer. Research suggests engagement in creative and imaginative activities, and establishes favorable epigenetic changes in the brain. Inheritance is dictated mainly by the arrangement of base pairs in DNA. Epigenetic changes involve chemical changes in DNA without altering the sequence. These alterations are erasable but allow transmission to subsequent generations.
Conclusion: World DNA day message to lawmakers
The discovery of the structure of DNA stands as one of the most significant scientific discoveries in human history. It is a lesson to all those involved in research and education, telling how great discoveries originated. It is intense curiosity, imagination and preparation rather than mere indulgence in technologies that clear the path for discovery and innovation. A society that advocates policies conducive to discoveries, also develops new technologies that follow. If we just borrow technologies from places where they originated, hoping for quick economic returns, the effort would be a gross failure. Students, determined to be the best judging from exam performance, engage in professional disciplines and perform exceptionally. Why are we short of discoveries and innovations in those disciplines? Will our lawmakers ever realize the issue? They need to wonder why we are weak in science and poor in innovation. Right policies can even reverse adverse epigenetic attributes propagating in a society!
By Prof. Kirthi Tennakone
ktenna@yahoo.co.uk
National Institute of Fundamental Studies
Features
Death of the Sperm Whale
REVIEWED BY Prof. Rajiva Wijesinha
Earlier this year, I sent her most recent book by an old friend, Kamala Wijeratne. Death of the Sperm Whale is her first book of poetry in four years, though in between she has published fiction, two books though both of them too were slim volumes. I am full of admiration for her in that she keeps going, the last of the poets whom I helped to a wider readership in the eighties, when I championed Sri Lankan writing in English, something hardly any academic was prepared to do in those conservative days.
Kamala’s subjects are those she has explored in the past, but the use of the plural indicates that her range is expansive. She dwells much on nature, but she deals also with political issues, and engages in social criticism. There are several poems about Gaza, the multiple horrors occurring there having clearly affected her deeply. She repeatedly draws attention to the slaughter of children, the infants sent by God only to be taken back. And she deals with the destruction of the life of a doctor, after his healing, a theme that has kept recurring in the ghastly world which is subject to the whims of the incredibly nasty Netanyahu.
The title poem is about a whale destroyed by ingesting plastic, a tragedy to which we all contribute, though those who ‘loll on the beach, their senses dulled by the burgers they eat’ could not care less. More immediate is the simple account of a friend whose infant had died in hospital, when they diagnosed pneumonia too late.
Contrasting with these urgent statements are Kamala’s gentle perceptions, as when she writes of her son supporting her as she walks, while she thinks back to the days she supported him; of a marigold growing in a crack in a shrine, offering obeisance with its golden flowers to the Noble One; of birds investigating her dining room and deciding not to build there, the male lingering ‘confused and irritated’ but eventually following the female through the window for ‘She was mistress after all.’
She is deeply interested in the passing of time, and its impact on our perceptions. The first poem in the book is called ‘First Poem of 2024’ when she ‘heard the weeping of the dying year’, and went on to meditate on how we have categorised the passing of time, while the universe moves on regardless.
She welcomes the return of the Avichchiya, the Indian Pitta, a bird that has figured previously in her poetry, after six months, but this time she spares a thought for his case against the peacock, which stole his plumes.
There are two personal poems, one about a former student who turned her back on her when she had achieved success, the other about being nominated for a literary award, but not getting it after the excitement of attending the Awards Ceremony. Swallowing her disappointment, she congratulates the winner, noting that she will not go into ecstasies the next time she is nominated.
Paraphrase cannot do justice to Kamala Wijeratne’s gentle touch, which has expanded its reach over the years. So,A I will end by quoting from her tribute to Punyakante Wijenaike, another of the distinguished ladies whose work I promoted, the one before the last to leave us. The tribute ends, recalling her most impressive work Giraya,
Like the nutcracker
That makes a clean cut
You cut the human psyche
To reveal its darkest depths
by Kamala Wijeratne
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