AN INTELLIGENT PERSON'S GUIDE TO GENETICS by Adrian Woolfson. Duckworth Overlook, 2004
PREFACE (p7-8)
The DNA record is an imperfect time machine that can help reconstruct our human past. DNA will also help shape our future since mankind will soon be able to redesign itself from "first principles."
We humans are at the cusp (beginning) of a new Enlightment, defined by the accumulated genetic knowledge that enables us to entertain the possibility of modifying our own "human nature" and of creating artificial life. This tremendous power for change is unprecedented.
Given these scientific and technologic discoveries and inventions, how will these advances be guided?
What is needed is a "manifesto for life," such as the ideas in this book about human life and its future possibilities.
1) THE DNA TIME MACHINE (p9-28)
Most of history has gone unrecorded, including the dialects, mannerisms, pastimes and preoccupations of countless individuals, cultures and civilizations who have vanished without trace. But there are glimpses. (p10)
The history of life is ancient, far older than the affairs of mankind. However, the unwitnessed events of prehistory are not completely opaque (hidden). All life, past and present, is linked by a common record written in the chemical code from which genetic material is made.
DNA consists of long sequences of four chemical "letters" --- C, T, G, AND A, which are strung together in different combinations like differently colored beads on a necklace. The information of DNA is encoded in the precise order of these four chemicals. The information is like writing, but uses fewer symbols. (p10-11)
To an archivist of past events, the DNA sequences of extinct and living things are precious, preserving the record of many aspects of the history of life on Earth. Specifically, DNA shows the record of a prodigious array of structures with each sequence having a unique story. It is the distillation of a relentless journey through time and circumstances. (p11)
Together, the DNA sequences comprise a patchwork of life's history stretching back to its origins. However, they must be pieced together with careful detective work since some of the pieces of the changes in the DNA sequences are lost and some are dissociated. (p11)
Living things are unique (in the universe) since they contain an internal record of themselves. The details of a creature's form and aspects of its behavior are computed from the coded information inside the tiny threads of DNA, which function as miniature instructional manuals for its construction and operation. The DNA database controls all events in living things, but only the most essential information is recorded. (p11)
The individual habits, dialect or lifestyle of humans are not recorded in DNA since they are only transmitted by social learning or they are lost forever. Genes encode the raw potential for speech, behavior and culture. However, in "higher" organisms their details are often filled in by experience (things learned). The extent to which genes constrain the cultural attributes of humans and other animals remains unclear, however. (p12)
DNA is unstable, and sensitive to destruction by enzymes, oxygen, water and sunlight. But it is possible to recover DNA from ancient humans and other animals. (p13)
DNA from ancient samples includes: (1) fragments extracted from human remains taken from a house in Pompeii dating to the eruption of Vesuvius in AD 79; (2) a 2400-year-old Egyptian mummy; (3) a 5000-year-old Ice Man found in the Tyrolean Alps; and the remains of the only known dodo flesh in the world from the middle 1600s. The dodos distinctive appearance gave few clues as to their origin. So it was a big surprise when DNA analysis showed that dodos were related to pigeons. (p14-15)
Most of the DNA obtained from ancient specimens is degraded into small pieces and contaminated with DNA from other species, such as bacteria and fungi. Investigating archeologists, anthropologists and biologists are themselves often sources of contamination. As a result, ancient DNA must be prepared with great caution. (p15-16)
Animals have two types of DNA, which differ in their size and storage site. Nuclear DNA contains the bulk of the genetic archive, including the parts needed to make living things. It is stored in the cell nucleus, a tiny compartment in the middle of the cell. Mitochondrial DNA, on the other hand, contains a very small and specialized set of genes involved in energy production. These are housed in minute cytoplasmic organelles called mitochondria. (p16)
Each cell has only a single copy of nuclear DNA but hundreds of copies of mitochondrial DNA. This fact reflects the large number of mitochondria each cell contains. Since there are more copies of mitochondrial DNA than nuclear DNA, DNA recovered from ancient specimens is usually mitochondrial in origin. (p16)
Differences between nuclear DNA and mitochondrial DNA sequences (p16-17)
The complete DNA sequence housed in a cell is known as its "genome." Complete genome sequences have been determined for an ever-increasing collection of organisms, including viruses, bacteria, yeasts, plants, worms, flies, fish, mice, rats, monkeys, and humans. Analysis of mitochondrial DNA recovered from Neanderthal bones has shown that our direct ancestors were in fact a separate species, which emigrated out of Africa and resembled us more closely than Neanderthals. (p19)
Multicellular life is known to have originated in a geological era known as the Precambrian, around the period of 600 million years ago. At about this time the thirty-two or so basic animal body plans, or phyla, which are the basic design templates for all living things, first appeared in the fossil record. One of these phyla, chordates, gave rise to all vertebrates, including mice and humans. (p25-26)
Once the genomes of all existing and all possible extinct species have been sequenced, it should eventually be possible to reconstruct life's complete evolutionary tree. (p26)
Eventually it might be possible to re-create the elusive ancestor of all life on Earth, a hypothetidcal organism known as LUCA, or the "last universal common ancestor."
2) How to build a living thing (p29-50)
3) Fabulous monstrosity (p51-74)
4) Smart genes (p75-104)
5) Reprogramming life (p105-124)
6) Making creatures from scratch (p125-145)
7) The limits of possibility (p146-176)
8) A MANIFESTO FOR LIFE (p177-208)
Despite the flexibility and plasticity of human culture, genes and their environmentally responsive programs have a more profound effect on our behavior and mental world than we might ever have imagined. (p204)
If every aspect of our behavior, thoughts, and emotions is shaped to some extent by our genetic programming, artificial modifications of these programs should enable key aspects of ourselves --- including our shape, lifespan, intelligence, sense of equality, capacity for compassion, love, sexuality, empathy, aesthetics, justice and morality, all once assumed to be inviolable aspects of our humanity --- to be modified or reconfigured from first principles. (p204)
Should we attempt to remodel ourselves? We could argue that it is precisely the paradoxical and irrational aspects of our existence which make us so uniquely and charmingly human. The philosopher David Hume argued that our negative attributes --- such as our propensity for greed, warfare, excessive ambition, dishonesty, indecision, lust, anger --- coupled with life's inescapable blights --- such as illness, suffering, frailty, mortality --- form an essential part of what defines us as humans. (p204-205)
From this perspective, modifications might fundamentally change our nature and might as a result be undesirable. We would also be running the risk of losing our capacity for free will and self-determination, the very characteristics that perhaps more than anything else define our humanity. (p205)
Through greed, indifference, incompetence, incomplete knowledge, or intrinsic limitations in our ability to compute the consequences of our actions, we might undermine the continued existence of the natural world that sustains us. (p205)
The intervening ethical and philosophical issues are important details --- perhaps the most important that mankind will ever have to consider. But they are details nonetheless.
Synthetic life is inevitable because we are intrinsically curious, because we have utopian desires. These are inalienable human characteristics. We will not be able to pass up opportunities that allow us to (improve human life) --- or to counter ideologies that threaten our way of life.
The inevitability (of our "synthetic biological future"), however, is not an excuse for complacency.
Our human species, called "Homo sapiens," has existed for around 130,000 years and was preceded by several very different species of humans:
[1] Homo rudolphensis
[2] Homo habilis
[3] Homo erectus
[4] Homo ergaster
Each of these human species came and went at a rate of one every 200,000 years or so. Each no doubt had its own perspective on human existence. (p206)
It would have been hard for any of these human prototypes to have imagined that human existence could be configured in any other way, even if their mental capacities had been sufficiently complex to do so. It is a largely irrational urge to preserve our current "incarnation" unchanged. However, human nature is not static. There is no rational basis for glorifying one aspect of life's evolutionary history and declaring it sacrosanct. The familiar is comforting. But then the human instinct to avoid ourselves changing is no doubt itself to some extent genetically programmed. (p207)
It is possible that the age of DNA technology will eventually be transcended, or at least profoundly modified. The information of life --- this time encoded by artificial means --- will explore combinatorial landscapes more powerful than those of RNA and DNA. These "explorations" will be littered with unimaginable possibilities. We may need to accept the idea that humans and all other DNA-based life on earth are not an end point in themselves, but "contingent beings." (p207)
We humans and other animals may best be understood and imagined to be "crucibles for the burning, baking and creation of life's future incarnations." (p207)
We might (in the distant future) sit (in a coffee shop) and laugh at the irrational behaviors of our predecessors --- who fell in love, lost their tempers, experienced jealousy, collected stamps, got ill, lived for only eighty years, and on occasion were discontented or unhappy. (p208)
We might alternatively be incapable of imagining what such things were! (p208)
BIBLIOGRAPHY (p209-229)
INDEX (p230-240)
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