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12
Jan
“Life begins at forty” is a well known saying that slips easily off the tongue. More profoundly Macbeth says “Life’s but a walking shadow, a poor player, that struts and frets his hour upon the stage, and then is heard no more“. Yet life must have begun somewhere, though its origin and essence remain elusive. Early in the King James version of the Bible, in Genesis, there is a description of how all the plants and animals were created and following that is written “the Lord God formed man of the dust of the ground, and breathed into his nostrils the breath of life“. Soon after that one reads “so God created man in his own image, in the image of God created he him; male and female created he them“. It is wonderful imagery and it involves something I want to investigate more, viz; replication. Crucially, I also want to consider the importance of the accuracy of that replication.
Regardless of your faith you may or may not believe in the literal words in the Bible. I myself was brought up to become a member of the Roman Catholic Church and so my early indoctrination was obviously coloured by its teachings. Over time I have grown at times closer to, but at other times further away from that institution. My main problem relating to all faiths has mainly been with their churches and clerics rather than with their holy scriptures. The Bible is inherently difficult because so much of it is written using parables and metaphors. It has also been translated and edited many times, thus leading to different versions.
The scriptures (as with all good books) contain much wisdom. I commend people to read them but advise caution in preaching interpretations to others and to also be wary of quoting them, often out of context, to try and make a point. Having said that, the opening words of Genesis are “In the beginning God created the heaven and the earth“. In parallel with this I was taught by Benedictine monks that the first question in the Catholic penny catechism was “1. Who made you?” and that the response should be “God made me“. The next question was “2.Why did God make you?” and the rote response was “God made me to know him, to love him and to serve him in this world, and to be happy with him forever in the next“. All very well I suppose except that, by my own logic, the second question should have been (and remains): “… then who made God?“
If I had asked the monks that question back in the fifties I would have been sure of a good whacking, just as much as if I had asked “We are told that God is omnipotent, so can he make a stone so big that he cannot lift it?” I know this is a type of “have you stopped beating your wife?” question, yet it is not invalid, other than we were not supposed to question anything. Just learn and believe what one was told. To simply submit, just as Joan of Arc, for example, was told to do before her demise. Children are wonderfully natural inquisitors – (so very different from the many hideous men who were the examiners and torturers within the Catholic Inquisition) – and which makes me remark:
JOYOUS KIDS
Watch children play,
Experimenters all,
Hear an adult talk,
And say I know it all.
The only line that I have found in the Bible that makes any effort about the origin of God is in Revelations (the Apocalypse of St John of Patmos), the very last book of the New Testament and which is not accepted as Canon by all Christian denominations. It goes “I am the Alpha and the Omega, the first and the last, the beginning and the end.” That still leaves a substantive answer ‘up in the air’. It is the sort of answer a clever politician might come up with. The creation and the origin of everything is thus so paradoxical and problematic, that I now use the word God less and less and tend to substitute the word Creator. Calling ‘God the Creator’ the ‘Alpha and the Omega’ does not help my understanding any more than the Big Bang theory does. Perhaps the word God could actually mean all that cannot be explained rather than being the personification of any entity, with or without any particular form. As for atheism, the spiritual Simone Weil said this: “An Atheist may be simply one whose faith and love are concentrated on the impersonal aspects of God”.
What is so really amazing is that stuff exists at all and my puny mind can only conceive of two alternatives of how that happened; either there was a time when there was nothing and some stuff came from nowhere or else stuff has always existed. Neither option seems knowable particularly without being able to grasp the intrinsic nature of time. It is not a major problem for me, because it is actually a wonder that there is an existence at all. Magic too is most wonderful when it remains unexplained.
When I was a teenager in Ireland I used regularly to cycle from home at Killegar via the “Rough Hill” to go ‘a cèilidh‘ at Kilbracken, where I would spend the evening before returning the same way after nightfall. Long parts of the road were quite straight. Thus whilst cycling (or pushing my bike up a hill) I would look upwards and night after night see the same star-patterns in the sky. I remember learning to recognise the standout constellations of Orion and Cassiopeia and, on those dark autumn nights when there was neither moon nor light-pollution, gaze at Cygnus flying to the West in the heart of the galactic haze that is our Milky Way. It’s said that Zeus placed Cygnus in the sky after the birth of his daughter Helen because her mother was Leda, whom he had seduced in the guise of a swan. Not the only time, of course, that a human conception arose from the intervention of a god.
I remember, vividly, the moment one night, when I paused, transfixed, on top of a hill at Kilnamar having suddenly become aware of the enormity of the visible universe; those countless points of light. It was both wonderful and deeply terrifying. How much space and light and how big the universe was and how small and insignificant I was in comparison. It was a crushing moment. Yet, sometime after, I realised that as insignificant as I felt, I was still a finite part of the whole. Really and truly. I was part of this huge universe; this creation and most pertinently this planet too. I was part of the ‘grand plan’. That means as much to me now as it did at that very special moment. And no one had taught me this. It was not from indoctrination that my perception and knowledge had grown. It was also a valuable lesson in humility.
Si I find myself unable to believe the literal biblical description of creation and in particular how Eve was formed from Adam’s rib. That inherent misogyny, so early on in ‘the good book’, looks much more like human than divine will. Adam and Eve’s adventure in the Garden of Eden reads like a metaphor for a child growing up. Not doing what it is told, losing its naivety and gaining the knowledge of good and evil as well as of mortality itself. Only mankind excludes itself from the Garden of Eden, which for me still exists as our own beautiful planet. Unlike the rest of nature I concur with D.H. Lawrence that only man “can slip entirely through the fingers of the hands of God” and only mankind is replicating itself out of all proportion to everything else on Earth. Going forth and multiplying has become an anathema. Too much replication and so consider:
POPULATION CONTROL
Lemmings are like pontiffs
When controlling population.
Instead of jumping off tall cliffs
They should have safe copulation.
I first began to seriously consider the question “What is life?” after Crick and Watson laid bare the structure of DNA and RNA with their description and understanding of the double helix and how genes are coded using only four simple chemicals (adenine, thymine, guanine, and cytosine). It is the ability of these four nucleotide bases to replicate themselves that has allowed species to come into existence and replicate; to conceive and give birth; to grow from a seed or a spore and thus to multiply. A reasonable starting point for defining the essence of life could be the inherent ability to replicate.
Now the fact that replication is not always exact turns out to be quite amazing because it is these little flaws, these mutations, that underpin biodiversity and evolution as well as contributing to the uniqueness of every human being. I simply cannot believe that the universe was created in seven literal days and that all the land species in the world came out of the ark after the flood. I do not want to make ‘creationists’ bend to my thinking but nor should they try and force their beliefs on others. I am always a sceptic when it comes to any form of evangelism with its smack of moral indignation and self righteousness and from where hypocrisy is only a step or two away. I try and use my own eyes and ears and brain to see and know what is around us, what is disappearing and what is self-evident in the fossil record. The ten commandments may have been written in stone, but literally written in geological stone, in layer upon layer of bygone days, is the see-able evidence that many creatures have come and gone and that man’s presence came very late and now has so much impact.
There are two fundamental ways by which species propagate life. Sexually and asexually. An accepted definition of a species is an organism that is capable of reproducing its own kind. Thus, for example, the two different species of a horse and a donkey can produce a mule, but because two mules cannot reproduce another mule, they are not a species; they are hybrids. Genetically, a horse has 32 pairs of chromosomes compared to a donkey’s 31 pairs. The mule is an aberration, a mélange and is not the result of a mutation. It receives 32 chromosomes from its mare mother and 31 from its jackass father which means that there can be no full pairing of its inherited genetic material. On the other hand a horse with cloven hooves or six legs would be a mutant and this would be confirmed if its offspring maintained the characteristics through generations.
Normal body cells multiply by mitosis, a process where there is an attempt to make exact copies of the parental DNA that had been formed at conception. That parental DNA is a mixture of genetic material originating from the four grandparents, but depending on which genes are dominant, only half of that DNA is expressed. The other half is still there, but it is dormant or recessive.
Germ cells or gametes (the sperm, ova, pollen, etc that will be involved in sexual reproduction) are formed by meiosis, a different process that deliberately shuffles the DNA (using a process known as cross-over) so that each and every germ cell is genetically unique. Not only unique, but also capable of atavism, which means they will be able to display traits that the grandparents had, but which may have lain dormant in the parents. Meiosis most commonly results in gamete cells that are haploid (having only one set of chromosomes). These are paired-up at conception by the fusion of two compatible gametes such as a sperm and an ovum. The normal end result is a new diploid individual with a full set of paired chromosomes.
Note that mitosis, meiosis and conception itself can all result in mistakes. For example; the creation of an individual with one missing or one extra chromosome or the creation of individuals that are neither 100% male nor 100% female. It is even possible for two sperm to fuse together in a fertilised ovum with catastrophic results. When a mother produces two eggs, which are then fertilised, twin embryos can be formed inside her. Occasionally these two individuals can fuse together early in pregnancy to form a single individual. Such chimeras (hidden twin syndrome) have cells in different parts of their bodies that contain completely different DNA. Conversely, a single fertilised egg can result in two individuals. The identical or Siamese twins that result from the full or partial splitting of an embryo some time after conception.
These anomalies of conception are beyond the scope of this essay, but it is worth pointing out that things are not always ‘black and white’. There are some who take up a rigid position on the determination of when a soul enters (and later leaves) a human body and there is the related question of when the essence of an individual life (or ‘personhood’) begins. Such things are complex and have huge legal and philosophical implications. There are also people who believe in ghosts, spirits, fairies and witches. I have no fixed opinion on such entities, merely noting how good quality electric light has made many of them redundant in my lifetime.
Normal sexual reproduction occurs with the fusion of two gametes (the germ cells such as sperm, ova, pollen, ovules, etc) to form a zygote (the single cell that is destined to become an embryo, a foetus and then a baby) . The resultant life form, as already outlined, is not formed simply from its parents’ genetic material, but more pertinently, from all of its four grandparents. Equally important is the fact that since each germ cell is unique then, leaving identical twins and other anomalies aside, each individual is also unique.
Asexual reproduction happens widely in the plant world. A potato tuber planted in the ground grows into another plant that is an effective clone of the original potato. A willow branch that falls into the ground can take root there and will be a clone of the original tree. Most dandelions produce embryos asexually by a process known as apomixis so most dandelion seeds, unlike pollen, are clones of their parent flower and which one can gaze at as they float away on the wind.
Asexual reproduction also happens in the animal world. This happens quite naturally when some animals are cut in half or break into fragments (such as flat worms) and also with ants and bees, where the males may be formed from unfertilised eggs. A queen honey bee can fertilise her own eggs, or not, with sperm she obtained on her honeymoon flight. The eggs that she fertilises turn into diploid females (with paired chromosomes) and the unfertilised ones become haploid males (the drones with just one set of chromosomes). The queen bee is in reality a slave as it is the workers who “instruct” whether she should make males or females by the size of the wax hexagons that they make. The queen only fertilises her eggs in the smaller of two different sized wax hexagons. The workers (all females) must replace (or supersede) a queen before her supply of sperm runs out or she will only be able to create drones and the hive would die. Before or just after they kill their queen, the workers can turn an immature worker grub into a queen by modifying its wax cell and feeding it royal jelly. Drone bees are thus de facto virgin births having arisen without sex and without the fusion of any gametes. Certain unfertilised amphibian eggs can also be stimulated into growth by pricking them with a pin instead of them being penetrated by a sperm and these too turn into males. My biology tutor once jokingly postulated that there could thus be a scientific basis for Jesus being a man, having been the result of a very famous virgin birth! This is not actually born out because the determination of sex (and intersex states) is much more complicated in nearly all mammals, including us. That will be the subject of a different essay.
Mutations are formed when DNA-copying goes astray and this is most common during the meiosis of sexual reproduction. Mutations can result in early death or malformation and some 25% of pregnancies miscarry because of such mutations. Yet mutations can also result in individuals with enhanced features. The great ability of viruses and bacteria to mutate is why our antibiotic strategies are coming under increasing strain as those microbes so cleverly adapt themselves to survive (and even prosper) in the killer environments that we try to create for them.
‘What is life?’ and ‘what is alive?’ are distinct questions. Individual animals, plants, fungi, bacteria, etc can be alive or dead but even dead individuals can still contain life if the genetic material within them can be stimulated to grow. It is one thing to bring back extinct animals theoretically, as in the movies, but in fact dead dogs have been used to create clones in Korea in a way analogous to Dolly the sheep, the first cloned mammal. The process of taking the nucleus from a somatic (body tissue) cell with its full complement of parental DNA and using it to replace the nuclear material in an ovum or immature embryo can result in clones; entities which are effectively identical twins with their “parent”. One could argue that the vast majority of cells in our body tissues are thus just as much imbued with individual life as are our sperm and ova. The irreverent lyrics of Monty Python’s “Every sperm is sacred” might need to be rewritten to include all organisms and every single cell.
My starting-point definition for the essence of life is thus; “material that is capable of replicating itself”. Most commonly, in nature, this is achieved when the DNA inside a cell starts making copies of itself in such a way that a new individual is formed. Viruses are a special case because they themselves are not cells in the conventional sense. They contain DNA or RNA inside a protein coat but can only replicate once entry to a host cell has been achieved, and which thus parasitised does the virus’s bidding. For me they are a form of life, even if they can only replicate inside their hosts. The question has been posed as to whether or not computer viruses are any different. They too infect their hosts, replicate and “fly off” to infect another computer. I believe that there is a fundamental difference and that is that viruses can quite naturally mutate but this doesn’t happen with those in a computer. Computer virus codes can only be changed by programming; they don’t have the capability to evolve on their own.
There is an interesting group of replicators that have nothing to do with genetic material. They are the prion diseases (infections?) such as mad cow disease and Kuru. These agents are a special class of brain proteins that have a certain shape. When a prion protein gains entry to the brain (usually having got into the body in a diet involving cannibalism) and makes contact with chemically identical normal brain proteins, it then causes the normal ones to change their shape (but not their composition) to that of the prion. A domino effect begins and when there are enough prions present, the brain becomes spongiform and the person or animal eventually dies. Such proteins are thus an abnormal component of living tissue that can replicate. However, as with computer viruses, they have no way to evolve or change.
Thus the essence of life for me is not only the ability to replicate but also the potential to evolve. René Descartes is credited with the phrase “I think therefore I am“. An alternative might be “I evolved therefore I am“. If, as some postulate, the first genetic material on earth was formed from nucleotides (the basic building blocks of DNA and RNA) in conjunction with simple proteins that arose spontaneously in a chemical soup made from earthly minerals and water stirred up by electrical storms, then perhaps life has always inherently existed in the otherwise inanimate molecules that form the Earth. From the Earth’s inception there would therefore always have been the potential for life to evolve. I now look out at the natural world and can see tiny precursors of our DNA everywhere. A supposed inanimate universe being actually a dead phoenix lying in wait for its resurrection. Piles of dust, some even in human form, waiting for the breath of life to be inhaled.
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