Selfish to the core (part 2)

As nature would have it, it seems that natural selection really takes place at the macromolecular level of the genes that constitute us. Before trying to exposit the workings of a gene as the de facto unit of natural selection, I shall define it for the benefit of the reader. The bodies of living beings are really macromolecular machines, in the sense that all living beings are made up of one or more cells that contain different types of molecules performing various functions. Now what grants each one of us our respective individuality is a particularly long molecule called the DNA. The DNA is like a blueprint to the psychobiological construct of the living organism that it inhabits. Each organism has a unique DNA which may differ relatively less from a corresponding DNA molecule of another member of its species but will nonetheless differ more when compared to the DNA of an organism belonging to a different specie class. This molecule is unique in many aspects, the foremost being that it belongs to a very remarkable class of molecules called the replicators. Such molecules have the ability to make copies of themselves pretty rapidly. This makes them ideal choices as 'blueprint archives' inside an organism, for a DNA can make numerous copies of itself that can get distributed throughout the cells in a body. Thus each part of the body can have in its possession, a consistent set of rules that correspond to various behavioral and physical characteristics of the individual.

Now a DNA itself is divided into pairs of macromolecular sections that are called the chromosomes. There are 23 such chromosomal pairs in the case of humans making it a total of 46 chromosomes that constitute what is referred to as our genome. Other plants and animals also contain chromosomes of their own but in a number different from that of humans. Now these 46 chromosomes are like 46 volumes of formatted and indexed information that constitute the 'blueprint' corresponding to an individual living machine. During sexual reproduction (in most cases) the offspring inherits half of its 46 chromosomes from its mother and the other half from its father. There is a reason we find it more convenient to refer to them as 23 chromosomal pairs rather than 46 chromosomes and the reason is as follows. The two volumes in each pair contain alternative instructions for a particular function or motif. If we suppose that pair number 16 contains information about 'the color of the eyes', 'the shape of the ear', ' literary aptitude' among many other things, then volume 16a (inherited from the mother) might contain the instructions 'brown', 'small' and 'Shakespeare' and 16b(inherited from the father) might say 'green', 'long' and 'George W. Bush Jr.'. Only one instruction in each case can be selected ( I exclude the case of multiple personality disorders for the sake of brevity :P) and the one selected is referred to as dominant. The alternative that is not selected is referred to as recessive and though that part of the chromosome does not perform any function for the individual in which it resides, it may be passed on to future generations.

Now that I have (to the best of my engineering abilities) provided a working definition of the DNA and the chromosome, let me try to do the same for a gene which is the pivot of all my purpose here. I have myself come across two different definitions of a gene which though not definitely contradictory, are not necessary equivalent either. One definition is that a gene is that unit of a chromosome which corresponds to the synthesis of a particular protein or enzyme. For example when the body is in need of glucose and there is lactose present in the environment, a particular gene in the body is instructed to synthesise an enzyme called beta-galactosidase, which is responsible for converting the lactose into usable glucose. The other definition of a gene is that it is that part of a chromosome which corresponds to a particular bodily function or characteristic of the individual say colour of the eyes or height. But in order to go ahead with this small exposition, I shall state Richard Dawkin's definition of a gene which he believes is a working definition for the gene. But that and my last bit on gene selfishness and gene selection in the next and concluding post.

Note: Though pretty late and pretty ungrateful to provide a disclaimer, I shall nonetheless go ahead with this one. All of what I have written is based upon my understanding of most of what is written in one book, little of what is written in a second book and almost none of what is written in a third book. These books are (in order) The Selfish Gene by Richard Dawkins, On Aggression by Konrad Lorenz and The Origin of Species by Charles Darwin. The first among these is highly recommended for a fantastic exposition on the 'gene selection' theory. It is succulent with multifarious examples of animal behavior and each point or claim made is substantiated with an extremely articulate line of reasoning. The second was referred to extensively in the first and I chanced upon it in my institute library. I didn't have patience to read more than a couple of chapters. The third book is an undisputed classic and an inspiration to many ethologists and biologists after its author and its eulogised importance compelled me to buy it from Crossword (many thanks to penguin paperback for bringing the Classics to the masses). But I found the arcane english prose extremely dry and soporific in parts. Plus, the very size of the book was intimidating and I chose suicide over enlightenment. But I do hope to evolve into a formidable reader myself someday so that I can confront that book. After all ,Darwin is the master of all braggarts mouthing evolutionary innuendo, isn't he? ;).