• Suman Srivastava

Will This Be the DNA Century?

Updated: Aug 26


Around two decades ago, I read a book called The Cosmic Serpent. It is a fascinating book written by an anthropologist, Jeremy Narby, which suggests that all knowledge is coded in our DNA and the shamans (the ‘medicine men’ of ‘primitive’ tribes) have found a way to decode that knowledge. ‘Modern’ societies are only just beginning to understand DNA (this book was written in 1998), while the shamans have known about it from ancient times.


I read this book at a time when such claims about ancient knowledge had not been weaponised into a political force by WhatsApp warriors. That was an era when books like The Tao of Physics were exploring parallels between modern physics and eastern mysticism. So The Cosmic Serpent felt like another step in the same direction.

Our knowledge and use of DNA has evolved a lot since the turn of the century, and I have read a few more books on the subject, so this is a good time to take stock of what I know and try to get my head around what implications this has for lay people like you and me.

DNA and Ancient Culture


Jeremy Narby starts his book, The Cosmic Serpent from the Amazon rain forests in South America. He was there to do field work to understand the culture of tribes who lived there. One of the things that intrigued him was the amazing medical knowledge of the shamans. He repeatedly saw them treating people for all kinds of ailments. And often using fairly sophisticated techniques. For instance, they used something called ‘curare’ that is a muscle relaxing substance. This is currently used by modern doctors as an anaesthetic during surgeries. But how did the shamans get to know of this product? Here is what Narby writes in his book:


Most of the time scientists balk at recognising that “Stone Age Indians” could have developed anything. According to the usual theory, Indians stumbled on nature’s useful molecules by chance experimentation. In the case of curare, this explanation seems improbable. There are forty types of curares in the Amazon, made from seventy plant species. The kind used in modern medicine comes from the Western Amazon. To produce it, it is necessary to combine several plants and boil them for seventy-two hours, while avoiding the fragrant but mortal vapours emitted by the broth. The final product is a paste that is inactive unless injected under the skin. If swallowed, it has no effect. It is difficult to see how anybody could have stumbled on this recipe by chance experimentation.

So the question is how did the shamans learn to do all this?

Turns out that some double headed serpents spoke to them when they were smoking hallucinatory drugs.


Yes, I know. The appropriate emoji at this point would be an eye roll. And the appropriate action would be to shut the book. But then Jeremy Narby discovered something that might be a coincidence or not. This is that all ancient civilisations have a symbol that is related to knowledge which looks like a multi-headed serpent. And the DNA looks like two serpents lying head to toe against each other. Coincidence?

Oh, the symbol on the right? That is the Caduceous, the symbol for modern medicine. The two snakes are there too.


This still doesn’t prove anything, but at least there is a promising looking rabbit hole to dive into. So let’s do that and learn a bit more about DNA.


The History of DNA


If you search for the greatest ideas of all time, Charles Darwin’s Theory of Evolution would be pretty high up on all the lists that you find. Darwin said that all living creatures had evolved from creatures that had lived before them, through a process that he called ‘natural selection’. The theory is simple and elegant. He showed empirically that new traits continually evolve in animals, and if one particular trait confers some advantage on the animal, then it will win out and all individuals in that species will acquire that trait over time. For example, as competition for food increased in the African grasslands, the ancestors of the modern giraffe, would have tried to reach the leaves on the taller trees. Animals with a longer neck would have an advantage, so over time all giraffes acquired long necks.


This simple and elegant theory had one major drawback. It was not clear how these traits were passed on to future generations. The sperm from a male fuses with the egg from a female and a baby is born out of the fertilised egg. How does the fertilised egg of a giraffe know that it should grow a longer neck? Often some traits skip a generation and appear in a grandchild. Thus a tall grandmother may have children of regular height, but a grandchild who is tall. How does this happen?


A priest called Gregor Mendel was the first to solve this problem. He was not a good priest, but he was good at statistics and he was good at biology. He did meticulous experiments where he crossbred peas which had different characteristics (colour of pea, colour of flower, height of plant etc) and came up with his laws of inheritance. He published this in 1866, but nobody took any notice of him or his paper for over three decades. It was only in 1900 that some scientists rediscovered his theories and it became accepted by the scientific community.


In modern language, we can say that he discovered genes. He found that genes exist in pairs with each parent contributing one gene to the pair. A gene might control one characteristic (say the height of the plant or the human being). Now if both parents have the ‘tall’ gene, then the child will definitely be tall. However, if one parent contributes a ‘tall’ gene and the other a ‘short’ gene to the pair, then one will become ‘dominant’ and the other will be ‘recessive’. An individual who gets this mismatched pair in her genes might become tall because of the dominant gene, but might pass on the recessive gene to her children. Or vice versa. That explains how tall parents can have short children and then tall grandchildren.


Scientists were now on a hot trail. They figured that if they could learn more about genes, they could unlock the ‘mystery of life’. Of course there was a lot to be done to understand what genes were made of, what they did and how they did it.


Nothing happened though for several decades. The first half of the twentieth century was the time when the focus of the scientific community was on the atom. The atom is the building block of the inanimate world and everyone was focused on that, while no one had the time to focus on the building blocks of the living world. It was only after the Second World War ended, that our story moved forward. But then the action was fast and furious.


Scientists soon discovered that all living things are made up of genes, and that genes are made up of DNA. The DNA of each species is different from all the other species. So all humans have the same DNA, but it is different from the DNA of chimpanzees. More work revealed that DNA was really a language which nature uses to pass on instructions. This language consists of just four letters - A, T, C and G.


In 1953, Watson and Crick discovered the double helix structure of the DNA. This means that the DNA is like a spiral ladder and the rungs on the ladder are made up of the four letters. They also discovered that the letters form bonds (or rungs on the ladder) only in a certain way - A with T, and C with G.


With these four letters, nature forms 3 letter words - ATG, GGT, CCT, GTA and so on. Using these words, nature is able to write the book of life for all life that currently lives on earth or has ever lived. Every bacteria, virus, plant or animal has DNA that are made up of these letters and these words.


These words tell the proteins in the body what to do. The words come together to form sentences and paragraphs - we call them genes. And all the genes in your body make up who you are as an individual - they form your genetic makeup.


In 2003, the Human Genome Project was completed, which meant that scientists had written down the entire sequence of letters in a human being. There are around 3 billion letters in one person, so that took a lot of work. That first project took billions of dollars, but today you can get your genome sequenced for around ten thousand rupees and this cost is falling all the time. All you have to do is take a sample of your saliva and send it to a lab.


All this is great, but what use is this knowledge to us now? And what use will it be in the

future? Before we discuss the uses of the DNA, it is useful to look at the development of our knowledge about the atom in the twentieth century. We can then return to the DNA, and see what we are able to do with it today and dream about what we will be able to do in the future by drawing parallels with the atom.


The Atom Century


The chart above shows the development of the atom. In the next quarter century, several scientists evolved our knowledge about atoms to where it is today.


All the major advances of the last century came out of our knowledge about the atom. Computers, nuclear power, materials like plastic, new kinds of fabrics, new kinds of alloys, fertilisers, medicines… And all those led to other amazing technologies like space travel, television, mobile phones and so on.


So, there is a pretty strong case to be made for calling the twentieth century, the atom century. The growth in our knowledge of DNA closely follows the path of the atom. Now let’s look at the current applications of this knowledge and then imagine what is possible in the future.

The DNA Century?

Imagine that your genome report has just arrived. Today the report will tell you the following: Which major diseases you are at risk of getting. Which diseases you may not get, but you may be bequeathing to your descendants. It will tell you about the efficacy of some major drugs like antibiotics including which you are allergic to. Finally, it may give you some more insights into your blood group which will be relevant if you donate or receive blood.


Would you pay ten thousand rupees for that information?


Today, you may not be able to do much with the information that this report gives you - except avoid some medicines and prefer others. However, this might change in future.


In 2020, Jennifer Doudna and Emmanuelle Charpentier won the Nobel Prize in Chemistry for inventing the CRISPER/Cas9. Think of this as a word processor for your DNA that will enable you to edit your genome such that you could add or modify your genes. The editing tool helped scientists develop the vaccine for Covid and is likely to help medical science in several amazing ways. Controversially, it may be able to help you choose what traits you would like your children to have. Is that ethical? I don’t know, but it is certainly possible.


It is clear that all this knowledge of DNA will help us in medicine. We will be able to monitor diseases that we are more susceptible to, we will have personalised medicine and there may be other benefits that we can’t even imagine right now. Similarly, it is obvious that knowledge of genetics and our ability to edit genes will help us in agriculture, as we create strains of crops that have more of the benefits we seek and less of the negatives.


What is more interesting to me is the role of DNA in other aspects of our life.


Our knowledge of DNA is already transforming our knowledge of history. Earlier, historians and anthropologists had to use techniques like carbon dating to figure out how old something was. Today, if we can find DNA from the teeth of bodies that died thousands of years ago. This DNA is able to tell us more about our history and evolution than was possible earlier. We now know that Homo sapiens weren’t the only species of humans on this planet, and that our ancestors not only shared the earth with other species of Homos, but also mated with them. Many human beings alive today carry DNA from a species that we call Neanderthals and also possibly from a couple of other species.


We have also learnt about the origins of present day Indians. Tony Joseph wrote a book called, Early Indians, where he compares the genetic make up of Indians with a pizza. Our base is made up of humans that came out of Africa 65,000 years ago. The sauce in made up of Harappans, who themselves were a mixture of the First Indians and a group that came from West Asia 9,000 years ago. The cheese are the Aryans who came here from Central Asia around three to four thousand years ago. And the toppings are other migrants that came in later, for example from the East.


DNA has also been used in forensics to establish the guilt or otherwise of someone being tried in a court of law. Already it is considered more reliable than fingerprints and other methods of connecting a crime to a person.


So DNA helps us learn about our own history and the history of life on this planet. But those applications don’t sound too far fetched. It is smart, but not the stuff of science fiction. But sample this - DNA can be used to make computers that are smaller and faster than computers that use silicon based chips. It turns out that while the world is getting excited about quantum computers, DNA based computers are more practical and are likely to provide the same benefits as the quantum ones.


History, Computers, Disease treatment, Disease prevention, Paternity tests, Ancestry, Forensics, Agriculture - that’s quite a long list of areas where knowledge of DNA is already making a difference. What else will happen in the future? In the 1920s, nobody could imagine that we would be using computers and mobile phones, flying to the moon and clogging the oceans with plastic. All those came from our evolving knowledge of the atom. So who knows what the rest of the twenty first century will bring as we develop our knowledge of the DNA. While we have been able to sequence the human genome, we haven’t been able to understand all of it. Large chunks of it are considered ‘junk DNA’ which just shows our ignorance rather than wastage on the part of nature. What can we learn once we are able to read and understand this junk?


Career Advice


In the 1967 movie, The Graduate, the character played by Dustin Hoffman was given some career advice by a friend of his parents. The advice was “Plastics”. The senior gentleman thought that there was a huge future in plastics and urged the younger man to enter that industry as soon as possible.


What advice would you give a youngster thinking about their career today?



 

Books worth reading

(Click to see a list of relevant books)



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