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Evolutionary Musings

“My ague has left me in such a state of torpidity that I wish I had gone thro’ the process of natural selection.” wrote Erasmus Darwin in his letter to his grandson, Charles Darwin.1 In the same letter, he stated that On the Origin of the Species was “the most interesting book” he had ever read. The book, however, also received harsh criticisms, and that bipolar opinion on the book that continues to this day. Indeed, I don’t think there has been any book in human history that generated such polarized opinions. I suspect the reason for this polarization stems from the word evolution, a word, ironically, Darwin didn’t use in the first edition of On the Origin of the Species . In this essay, I want to go over some arguments for and against evolution.2 As to why I am writing about evolution, I will come back to it at the end of this essay. Fossils of Crinoid columnals found in Utah (courtesy: Wikipedia) The Fossil Record: If evolution occurred, then one would expect to see intermediate f...
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Charles Darwin and His Theory of Natural Selection

 In 1838, a prolific writer compiled a list of pros and cons to decide whether to “marry” or “not marry”.1 Some of the pros for marriage included having children and having a constant companion (and a friend in old age), someone he could love and talk to. But bachelorhood also offered some compelling benefits like having the freedom to go anywhere and having more free time in general. With that freedom, the writer reasoned, he would be able to enjoy intelligent conversations with “clever men at clubs.” That writer was Charles Darwin, the father of evolutionary biology. Charles Darwin (Courtesy: Wikipedia) Charles Robert Darwin was born in Shrewsbury, Shrewsbury, England on 12 February 1809. He was the fifth child of Robert Darwin, a doctor, and Susannah Darwin. In 1825, he worked as an apprentice doctor under his father’s supervision and eventually was sent to the University of Edinburgh Medical School. He, however, neglected his studies because the medical lectures bored him and s...
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Vaccine Development II: Strategies

In the first part of this series on vaccine development, I went over how our immune system responds to pathogens like viruses or bacteria. Briefly, when our body encounters a novel pathogen, specialized cells from our immune system create antibodies that bind to specific molecular signatures called antigens found on that pathogen. The blueprints for effective antibodies are retained as memory so that we can quickly produce large quantities of those antibodies when needed.  To develop a vaccine that can protect us from a particular pathogen, hence, we need to somehow elicit these responses without getting sick from that disease. In this essay, I will describe how researchers try to achieve that.1 Let’s come up with some strategies with the information we already have from the first part of this essay. Assuming the antigens are present, can’t we use dead pathogens to elicit the same immune response? Indeed, in the 19th century, scientists discovered that inactivated or killed micro...
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Vaccine Development I: Overview of the Immune System

When we read about deadly infectious diseases, we often feel life is unfair. After all, why can’t our body fight of the invading microorganisms and keep us safe? In reality, however, our body possesses amazing defense capabilities: our immune system routinely protects us from a vast army of pathogens—the organisms that can cause diseases. While our immune system excels at eliminating a previously-encountered pathogen, it also tries its best when it does encounter a novel pathogen. In this essay, I will provide a brief overview of how our immune system works and how it relates to vaccine development.1  Elimination of pathogens (Courtesy:  https://www.britannica.com/ ) Our immune system can be broadly classified into two systems: the innate/general resistance system and the adaptive system. The innate system may be able to eliminate a pathogen on its own or it can stimulate the adaptive immune system to become involved in eliminating the pathogen.  Let’s see how the innate/...
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A Chess Story and Testing for Coronavirus

Chessboard (Courtesy: pixabay.com) Once upon a time, there lived a brilliant sage in a faraway country. One day, inspired by a vision, the sage developed the game of chess. Brimming with euphoria, he went to the king to explain the game. After listening to the sage, the king was intrigued. “I will give you anything you want,” the King declared excitedly, “Chess is marvelous!” The sage, however, shook his head and told the king that he didn’t need anything. The King was not happy; he insisted that the sage asks for a reward. The sage gave up and told the king that he would be happy with some grains of rice distributed in a specific way: one grain of rice on the first square, two on the second, four on the third, eight on the forth, and so on for all the 64 squares on the chessboard. The number of grains, in other words, would double on the adjacent square. The king, baffled by this strange request, summoned his treasury to calculate the number of grains the sage would get. After som...
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What Do We Think of Viruses?

Coronavirus (Source: CDC) It has been a while since I have written anything on this blog, and I missed that. But sometimes you need to take care of things that simply can’t wait. For example, taking some time off to take care of your sick father. Under those circumstances, even when you are not actually looking after someone you love in person, it’s the constant worry that gets you. At the very least, that worry got me, and that’s something that has been in my mind all the time for the last few months. But now that I don’t have to worry about that anymore, I can focus on this blog again. I hope to write regularly from now on. There is something else that most of us are worried about now though: coronavirus disease 2019 or COVID19 (to learn about the most recent developments on COVID19, please visit CDC’s website ). I intend to write a few essays on viruses, and this would be the first one. Here, I am going to focus on a question that might seem strange without any biology backgro...
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What Can Worms Teach Us?

If you are the world’s safest driver, can you expect your children to be safe drivers as well? Will they avoid dangerous driving situations when they first learn to drive? Short answer: most likely not. Long answer? At least in some organisms, the offspring can inherit some life-saving tips from their parents. For example, in Caenorhabditis elegans , a free-living transparent worm, parents can learn to avoid toxic food source and their offspring learn to avoid that food source without ever encountering that food. In their recent paper , Rebecca Moore and her colleagues described how the offspring inherit this information. C. elegans moving! Courtesy: Wikipedia Both in animals and plants, the environment greatly influences physical and behavioral characteristics. These characteristics sometimes can be passed onto the next generation even though the genetic code, the DNA sequence, remain unaltered (read this essay   for more information on the genetic code). The biological m...
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