Click the title or click the date below (five half-hour episodes):
In this five-part series, Jonathan Miller returns to his roots in medicine and tells the story of how we came to understand reproduction & heredity. Disposing with the idea of an external, perhaps even supernatural, vitalising force, he describes how we have arrived at the picture of ourselves and all organisms as Self-Made Things.
- 27 JulyProgramme 1
Darwinism in the second half of the 19th century gave us a theoretical framework that captured in one stroke the seemingly limitless variety that zoologists, botanists and paleontologists were finding in every dimension in nature.
On a macroscopic scale, it seemed that everything from extinctions and new species in the fossil record to the mating displays of birds of paradise and the pattern of a butterfly's wing was within reach of scientific explanation. If the new feature were good for survival and propagation, it stayed. If not, it fell from this new tree of life.
And yet, at a finer level, explanations of how these variations came about, and where they entered the process, were still wanting. Indeed it became clear that we couldn't even describe satisfactorily how species bred true to type, without variation, let alone how eye colours and claws change over time. Why does a duck give birth to a duck rather than a platypus?
In the first part of this series, Jonathan Miller looks at organisms that make things other than themselves. Nests, webs and dams are all part of what Richard Dawkins described as the "extended phenotype" of a species. A termite mound is as much a part of the identity of a termite as its white thorax and strong mandibles. Does looking at the way things make things give us clues as to how they make themselves?
- 3 August
This week Jonathan Miller looks at the birth of ideas about reproduction and heredity. Starting with the ideas of Aristotle and the early Greeks, he argues that because knowledge of underlying structures such as cells and genes are comparatively recent, it was necessary for thinkers addressing the problem, right through the renaissance, to resort to immaterial agents acting upon the raw substances of fertilization.
When addressing theoretical problems, the human tendency to look for purpose rather than mechanism, especially with an issue as fundamental to our condition as reproduction, has taken a long time to disappear from our investigation.
Aristotle's influence on embryological thought was considerable for much of the classical period. But in the 2nd Century AD the Graeco-Roman physician Galen introduced for the first time his rigorous anatomical technique to the argument.
However, it was William Harvey, best known for his work on the circulation of the blood, who made the next major contribution.
But as Jonathan Miller suggests, what links these three thinkers is their epigenetic approach to reproduction. To them, lacking as they did knowledge of any ordered material substrate for explanation of the interaction between semen and the womb, the foetus somehow condensed out of unordered mass.
Prof Sir Geoffrey Lloyd
Prof Vivian Nutton
Prof Simon Schaffer
BBC History - William Harvey
- 10 August
This week, Jonathan Miller describes eighteenth and nineteenth century efforts to identify the cell as the underlying structure of living things.
It's sometimes suggested that the English microscopist Robert Hooke discovered the cell in the mid-seventeenth century, but as Simon Schaffer tells Jonathan, the 'cells' that Hooke saw in sections of cork were empty, and Hooke only called them 'cells' because they reminded him of monkish cells in a monastery.
The question of how to describe bodily structures before a conceptual framework existed was a real problem for those biologists trying to understand the inner processes of life.
Janet Browne explains how French scholars used a terminology of fibres and textiles to describe what they saw through the microscope. Paul Nurse argues that, in their efforts to identify and describe the basic units of life, nineteenth century biologists borrowed the concept of the atom from physics, and tried to apply it to the living world.
The major embryological breakthroughs came in Germany. Nick Hopwood describes how Christian Pander and Karl Ernst von Baer created a new language of 'germ layers' to describe the early embryo.
Although the German duo, Schleiden & Schwann, are often credited with the actual discovery of the cell, historians like Robert Olby give them credit for focussing attention on the cell, even though their descriptions of cell division as a process of crystallisation or precipitation were eventually shown to be wrong.
Prof Simon Schaffer
Dr Nick Hopwood
Prof Janet Browne
Prof Paul Nurse
Prof Robert Olby
- 17 August
This week, Jonathan Miller describes the research that eventually led us to identify the gene as the key agent of inheritance.
One of the most important figures in this search was a nineteenth century Augustinian monk called Gregor Mendel. Robert Olby tells Jonathan about Mendel's hybridisation experiments which showed for the first time that plants inherited characteristics according to a mathematical pattern. Mendel recognised that characteristics could be recessive or dominant, so that traits could 'disappear' from one generation and 'reappear' in the next.
In 1859, Charles Darwin published 'On the Origin of Species' which laid out the theory of evolution by natural selection. But as Enrico Coen says, Darwin had little idea about the actual physical processes of inheritance. He thought that hereditary particles representing each part of the body - he called them gemules - were somehow collected together and passed on to the next generation. The fact that circumcised males managed to pass foreskins on to their male offspring was something Darwin was unable to explain.
The ideas of Darwin 's contemporary, the German biologist August Weissmann, were far more convincing. Richard Dawkins is full of admiration for Weismann's concept of a river of hereditary particles, insulated from environmental influences, flowing through the generations and determining the characteristics of individual species.
But as Evelyn Fox Keller argues, it wasn't until the beginning of the twentieth century that scientists began to realise that the key to inheritance lay as much in the mechanisms that activate the genes, as in the genes themselves.
Professor Robert Olby
Professor Enrico Coen
Professor Richard Dawkins
Professor Evelyn Fox Keller
- 24 August
In the final programme in the series, Jonathan Miller brings the story of reproduction and generation up to the present. He hears first from Nobel prize-winner Sir Aaron Klug who describes the work done by Crick and Watson in 1953 to identify the chemical structure of deoxyribonucleic acid, better know as DNA, which they represented as a double helix.
But as Jonathan argues, since the discovery of DNA, we've had to face up to the enormous complexity of the cellular and genetic mechanisms that enable us to be 'self-made things'.
Lewis Wolpert stresses the importance of the proteins that the genes code for, and the control regions that determine when and where a particular gene is turned on.
Claudio Stern explains how, despite their identical genetic inheritance, dividing cells begin to differentiate and commit themselves to becoming different body parts.
Tim Horder describes Hans Spemann's discovery of a command centre, now known simply as the Spemann Organizer, which sends out signals that inform cells what body parts they should become.
Ever since he was a zoology student, Jonathan has been interested in how many animals, including ourselves, are organised into serial segments. Peter Lawrence explains some of the principles of serial segmentation, and warns Jonathan against assuming that internal genetic segments will necessarily coincide with the external segments that we see with our eyes.
Enrico Coen draws all these threads together in a metaphor that likens our ability to make ourselves to the relationship between a painter and a picture. But rather than there being a distinction between painter and canvas, we have to understand that living things are both painter and canvas. We are the product of an interactive dialogue in which both painter and canvas are interdependent.
Professor Sir Aaron Klug
Professor Lewis Wolpert
Professor Claudio Stern
Dr Tim Horder
Professor Peter Lawrence
Professor Enrico Coen