The Story of Genetics, Development and Evolution

A Historical Dialogue

Gáspár Jékely

• Publisher: WSPC (EUROPE)
• Year: 2017
• eBook ISBN: 9781786342553
• Topic: Biological Sciences
• Subtopic: Philosophy History & Theory
• Index: Biological Sciences

This unique story offers an introductory conversation to genetics, embryology and evolution, taking us on a historical journey of biology through the ages. Using a series of dialogues between the Greek philosopher Democritus and his disciple Alkimus, we travel through time visiting eminent scientists throughout the centuries, from Lazzaro Spallanzani and Theodor Boveri to Francis Crick, Max Perutz and Christiane Nüsslein–Volhard. We find ourselves at the intersection of competing theories in biology and witness the progression from the debunking the theory of spontaneous generation to the mapping of the genome. Attention is given not only to the great successes in the field but also to the equally important and exciting failures.

Originally published in Hungarian, The Story of Genetics, Development and Evolution provides a historical background to the life sciences, with complex scientific concepts stripped down and explained carefully for academics and anyone interested in going back to the roots and philosophies of scientific progress.

Translated from: Jékely G Master, are you awake? A fictitious dialogue on genetics, development and evolution. 2006, Bratislava: Kalligram

Contents:

• Preface
• At the Harbour
• At the Market
• Part One:
  • The Mystery (and Sperm) of Life's Origins
  • Deux Ex Machina
  • The World Egg
  • Spontaneous Generation and Meat Broth — Lazzaro Spallanzani
  • Types and Rhythms of Embryos — Karl Ernst Von Baer
  • Cell From a Cell
  • The Feats of the Sea Urchin
• Part Two:
  • Chromosomes, Mendelian Factors and Evolution
  • Roasted Capon
  • The Immortal Germplasm
  • Reduction Division
  • A London Pigeon Sale — Thomas Henry Huxley
  • The Orchard of Evolution
  • Peas and Minotaur — William Bateson
  • Galton and Mendel
  • Two Sperm, One Ovum — Theodor Boveri
• Part Three:
  • The Triumph of Genes
  • Trickster Mendelians — Thomas Hunt Morgan
  • Sex Chromosomes
  • The Telltale White Eye
  • Genetic Mapping
• Part Four:
  • Forces and Reactions
  • The Mathematics of Life — D'arcy Wentworth Thompson
  • The Two-Headed Newt
  • Zeus's Beard
  • Evolutionary Synthesis
  • The Casting Moulds of Genes — Hermann Joseph Muller
  • Fronts On the Wings of a Moth — Alfred Kühn
  • The Birth of Patterns
• Part Five:
  • The Atoms of Life
  • Hormones in Larva Blood
  • One Gene, One Enzyme — George Wells Beadle
  • The Protein-Genes
  • The Principle of Transformation — Oswald Theodore Avery
  • The Triple Helix — Linus Pauling
  • DNA with Ambrosia
• Part Six:
  • Codes and Links
  • The Central Dogma — Francis Crick
  • The Diamond Code of Proteins
  • The Genetic Code
  • A Molecular Lung — Max Ferdinand Perutz
  • Sugar-Consuming Bacteria — Jacques Monod
• Part Seven:
  • Genes in the Mortar
  • Epigenesis and Genetics — Conrad Hal Waddington
  • A Recipe for Making Mice — Sydney Brenner
  • The Wiring of a Worm's Brain
  • Recombinant DNA
  • Striped Embryos — Christiane Nüsslein-Volhard
  • Our Worm Ancestors — Detlev Arendt
  • The Age of Genomics — Eugene Koonin
• Part Eight:
  • Beyond Genes
  • Postcard to Thrace
  • The Cedar Forest of Abdera
  • The Philosophy of Biology — Ernst Mayr
  • The Genetics of the Biosphere
  • Biscuits Baked in Ash
  • On the Island of Bensalem — Pál Nagy-Juhász
• Epilogue
• On Mount Olympus
• The Bay of Abdera

Readership: Students of biology, philosophy and medicine and anyone interested in the history and philosophy of biological discoveries.
Keywords:Genetics;Evolution;Democritus;Spontaneous Generation;Embryology;Genetics;Developmental Genetics;Molecular Biology;Evolutionary BiologyReview: Key Features:

• Entertaining and didactic style
• Uses an historical perspective to allow the gradual learning of the subject
• Conversational structure
• Synthesizing different disciplines thus providing an integrative understanding of biology

Part One

The Mystery (and Sperm) of Life’s Origins

Deus ex Machina

EXTON: Ah, Exton, you’ve done well. They’re making their way. Now, let’s see. A little more chronic turbulence and here they are. The old codger, too.

DEMOCRITUS: Alkimos, Alkimos, where are you? I can’t see a thing in this thick fog.

ALKIMOS: Here I am, master, over here!

DEMOCRITUS: I don’t know what’s happened to us. I’ve never been swept into such a vortex, not even when I visited the Oracle of Delphi. My head is spinning.

ALKIMOS: Hold on to me. I see a gate over there. Let’s see what lies beyond it.

DEMOCRITUS: I don’t understand. Maybe it was the wine. Alkimos, you’ll have to lead the way.

ALKIMOS: Here we are, but the gate doesn’t want to open. I fear the Heavens are playing tricks on us. I’ll have to force it. Kronides! Master, look! I’ve never seen the likes of this! Is this Olympus? Have we arrived at the home of the Cloud-Gatherer? Such lustre, such brilliance!

DEMOCRITUS: I’m blinded. Alkimos, I see nothing but glitter!

EXTON: Greetings.

ALKIMOS: Who’s speaking? Oh dear Zeus, is it the Cloud Gatherer himself? How my heart pounds!

DEMOCRITUS: Alkimos, you heard something too? There’s someone here!

EXTON: Have no fear, my friends. Come in, come in!

ALKIMOS: Oh, the immortal Zeus! We’ll sacrifice one hundred oxen, but please spare our lives. We didn’t mean to intrude. We drank too much wine and lost our way.

EXTON: You have nothing to fear. I’m not Zeus. I’m only a mortal being such as yourselves. My name is Exton. You were brought here because of your great desire for knowledge.

DEMOCRITUS: Where are we?

EXTON: Alexandria. This is the Deus ex Machina Centre for the Teleportation and Training of Philosophers.

ALKIMOS: Master, did you hear that?

DEMOCRITUS: I don’t understand, son.

EXTON: You were brought here because of your deep and enduring desire for knowledge.

DEMOCRITUS: By whom?

EXTON: Let’s just say the gods. I’m here to acquaint you with all the revolutionary discoveries that have been made about the living world during the past centuries.

ALKIMOS: What are you talking about? The past centuries? But my master knows everything about the earlier developments of philosophy.

DEMOCRITUS: This is true, stranger. What revolutions are you talking about? Some new nonsense devised by the Athenian philosophers? My master Leucippus and I have developed the most complete theory about the origin and properties of all living things. Of course in Athens they don’t read my treatises. Such abominable insolence.

EXTON: Perhaps it’s difficult for you to understand, but with the help of our newly developed Deus ex Machina you’ve been sleeping for 2400 years. We are now in the year 2015, after Christ. Since you fell asleep in the sands of Abdera, the Earth has circled the Sun 2400 times.

DEMOCRITUS: What gibberish. The only thing circling is the stupidity in your mind.

ALKIMOS: Certainly not the Earth.

DEMOCRITUS: And who is Christ? Is he that troublemaker—that Athenian philosopher who refuses to acknowledge my work?

EXTON: I see you don’t understand. You’re in Alexandria. About three thousand years have passed since the Trojan War. You have a unique opportunity to witness the awe-inspiring changes that have taken place in the study of the living world over the centuries. I’ll be your guide, but you’ll need to work hard to understand. So what do you say—would you like to undertake this journey? If not, I’ll return you to the sands of Abdera and provide you with a full flask of wine to compensate for your everlasting ignorance. Now decide, because there are several Athenians on the waiting list.

ALKIMOS: Master, let’s leave this place. We’re being fooled with. We shouldn’t believe a word he says. He must be a god, or demigod—his words are full of scorn. Let’s take our full flask of wine and depart, quickly!

DEMOCRITUS: Alkimos, there’s no point. You cannot escape the power of the gods. They’ll find us, no matter where we hide. Let’s try instead to overcome our suspicions and have a look around in this strange, but interesting world. We might even gather a few crumbs of this knowledge we crave. Yes, I’m going to stay, and I advise you do the same.

ALKIMOS: Of course, master. I have no other desire than to learn. But I’m not willing to sacrifice my life for this knowledge. I can do without crossing the River Styx for a while.

EXTON: So you’ve decided? If you don’t want to stay, grab your flask and leave quickly through the gate. Now let’s see … the next name on the list is Diogenes.

DEMOCRITUS: Who? That Sinopean fool? You mean he’ll gain that knowledge instead of us? Alkimos, we can’t allow that!

EXTON: Ah, I’ve persuaded you. My assistant Hermes will spread the news: the visitors have arrived! Now my friends, bathe and get dressed. Hermes, bring them soap and a change of clothes! Oh, and a lice comb!

DEMOCRITUS: Diogenes, hah. That worm of a simpleton. If I ever tell the others about this in Abdera …

ALKIMOS: Master, the water is foaming!

DEMOCRITUS: Ah, so it is. How odd! But we must accept what the gods provide.

ALKIMOS: And look at these clothes. They’re splendid!

EXTON: Are you ready? Can we go?

DEMOCRITUS: Wait a moment, Exton. You have to understand, we’re overwhelmed. Our loins are covered in clothes with metal teeth; we’re surrounded by materials and smells unknown to us; in the glass on the wall, we see our own shaggy faces. The image is so clear, so unlike the reflections we see in a bronze plate or water. I’m afraid the Deus ex Machina has blinded us with its brilliance and left us a bit worn out.

ALKIMOS: Yes, my master is right. Please understand, dear Exton, at the moment we’re too exhausted to face the knowledge of your age. Maybe you need to show us first how the distant future can satisfy our hunger and thirst. Nothing special, of course, just a pitcher of honey wine, roasted capon, and some partridge eggs, or some other simple food. After all, we haven’t eaten a morsel for almost three thousand years.

EXTON: I’ll see what I can do.

ALKIMOS: Thank you for your generosity. We can see you have a noble heart.

EXTON: I’ll be right back.

ALKIMOS: Master, if we’re staying, let’s have a look around. What is knowledge good for if we don’t know anything about the foods, the people, and the cities of this future world? Let’s see what the women of Alexandria are like three thousand years after the Trojan War! When we return home, you’ll need to have good stories to tell at the marketplace. Trust me, nobody’s going to care about your profound knowledge if it turns out you had no dalliances with a woman not yet born.

DEMOCRITUS: Son, quiet. What guides wisdom is not what guides our human companions. Anyone can admire food and women. We were brought here because of our powerful desire for knowledge, and we must not diverge from that path if we are to experience this miracle of the gods. People and food don’t change, but our knowledge does, increasing with the passage of time. We need to find out what the philosophers have discovered about the living world. What makes living things move? What gives them their unique shapes and their ability to survive and reproduce? What secrets reside in a plucked flower or a ripe fruit? Yes, Alkimos, we must remain true to our task. This is the only way we can learn about the wonders of life.

ALKIMOS: I understand, master. We must forget about Earthly pleasures and imbibe only knowledge. Philosophy may not be able to alleviate out hunger, but it’s good for something.

EXTON: Here I am, my famished guests. I’m afraid it’s a modest meal, but it should fill you up.

DEMOCRITUS: Thank you, dear Exton. This will keep our hunger pangs at bay.

ALKIMOS: Where are the partridge eggs and wine? What kind of mouldy pie is this?

The World Egg

DEMOCRITUS: Dear Exton, thank you for the fine food. But now, in keeping with our true mission, let us turn to wisdom. I believe your knowledge is so vast and varied that we shall only absorb it if we approach it slowly and with the appropriate humility. One day will scarcely be enough for us to comprehend a thousand years of knowledge.

EXTON: Yes, that’s true. But you won’t be here for just one day.

ALKIMOS: Master, you mean we’ll have more time to uncover the mysteries of life?

DEMOCRITUS: It appears so. How fortunate for us. You see, son, life is a complicated tangle. All around us it clatters. However, I worked out a coherent theory to explain it. All life was created from the clustering of atoms with like properties; it is a consequence of the atoms’ most inner traits.

ALKIMOS: Yes, master. Crooked with the crooked and smooth with the smooth.

EXTON: Indeed, Democritus’ mechanistic atom theory provided a far better explanation than the alternatives, such as the ancient myth of the world egg. Of course, the idea of the world egg has its beauty as well. Let’s read what Aristophanes had to say about the origins of the world in his comedy The Birds:

In the beginning there existed only Chaos, Night, Black Erebus and Dreary Tartarus: there was no Earth, no Air, no Sky. It was in the boundless womb of Erebus that the first egg was laid by black-winged Night; and from this egg, in due season, sprang Eros the deeply-desired, Eros the bright, the golden-winged. And it was he, mingling in Tartarus with murky Chaos, who begat our race and hatched us out and led us up to the light.

ALKIMOS: The egg emerged from nothing, and from it hatched the bird, life, love.

EXTON: Indeed, we’ll need to talk a lot about whether life sprang from non-living or living material. The first is known as abiogenesis and the other reproduction.

DEMOCRITUS: The world egg was produced through abiogenesis, but it created further lives through reproduction.

ALKIMOS: In other words, it laid eggs.

DEMOCRITUS: Probably.

ALKIMOS:

With a grunt the Cosmos spontaneously laid a speckled egg, From which hatched Life, light radiating its heat.

DEMOCRITUS: With the mixing of the atoms in the eggs, life is born again and again. From a formless mass sprang a feeling-moving creature.

EXTON: This is the process by which an organism forms. It’s the subject of embryology and developmental biology. I’ll have a lot to say about that.

ALKIMOS: Exton, if we solve all these problems we will have uncovered the key that unlocks the mystery of life.

EXTON: Perhaps.

ALKIMOS: The origins of the world egg.

EXTON: The Greek pioneers in embryology probably had similar dreams. The first detailed embryological observations were made by Hippocrates and his students on the island of Kos. Often we don’t know if the books produced by the Hippocratic School were written by the master or his students. Of course, this doesn’t diminish the value of this wonderful institution. The Hippocratic School formulated detailed mechanistic explanations of embryonic development. For example, here is a quote by Hippocrates, or one of his students:

[The embryo] is set in motion, being humid, by fire, and thus it extracts its nourishment from the food and breath introduced into the mother. First of all this attraction is the same throughout because the body is porous but by the motion and the fire it dries up and solidifies; as it solidifies, a dense outer crust is formed, and then the fire inside cannot any more draw in sufficient nourishment and does not expel the air because of the density of the surrounding surface. It therefore consumes the interior humidity. In this way parts naturally solid being up to a point hard and dry are not consumed to feed the fire but fortify and condense themselves the more the humidity disappears—these are called bones and nerves.

DEMOCRITUS: That corresponds to my beliefs. For some time I have stated that the external shape of the embryo develops before the internal organs form. This is the crust according to Hippocrates.

ALKIMOS: And what do you think, master, about the fire?

DEMOCRITUS: Hm, the fire … I suppose the fire animates the atoms.

ALKIMOS: But what is this fire, master? What is the flame that burns in all living things and is extinguished at the moment of death?

DEMOCRITUS: I don’t know, son. That’s something we’ll have to investigate.

EXTON: The spark of life or vis vitalis. The core idea of vitalism.

ALKIMOS: This fire can only come from Eros. The flames of Eros send us into the arms of a woman, so we may light the fire of a new life.

DEMOCRITUS: But it was Hermes’ flame and seed...

Table of contents

• Cover
• Halftitle
• Title
• Copyright
• Dedication
• Contents
• Prologue
• Part One
• Part Two
• Part Three
• Part Four
• Part Five
• Part Six
• Part Seven
• Part Eight
• Epilogue
• Appendix
• Further Reading
• List of Figures
• Index