Monday, December 8, 2014


For a long time I have been confused by the terms DNA, Genes, and Chromosomes and what do people mean when they say we have good or bad genes. After reading "The Selfish Gene" by Richard Dawkins (Oxford University Press, 1976), I have a clearer picture. With the help of the graphics enclosed, here is an explanation of what are genes, DNA and chromosomes:  

Our bodies are made up of thousands of millions of individual cells. Each cell contains your DNA (Deoxyribonucleic acid) – a molecule with a complete set of instructions for making your body.
The double-helix DNA is made up of strings of A,T,C,G* nucleotides stringed together in a particular sequence with  "A" always pairing with "T" and "C" with "G"
 *Adenine, Thymine, Cytosine and Guanine.
A gene is a particular length of DNA with a particular sequence of A,T,C,G pairing; that has properties which enable it to survive several generations e.g. a Blue eye gene, a Brown eye gene, a group of genes that build long legs, genes thar make you intelligent, cruel, kind, athletic, etc. Also genes that cause baldness, cancer, short-sightedness etc.
Using the analogy of a library, think of the body as a giant building that is the library. Thus:
Body= A giant building that is the library
Cell = thousands of millions of rooms in the building.
Inside the cell: Cell nucleus= a book case in the room containing volumes of loose-leaf binded books whose pages are inter-changeable.
Inside the cell nucleus: 23 pairs of chromosomes= 23 paired volumes of books in the book case.
Pairs are like Volume 1a to 23a paired with Volume 1b to 23b
Gene= a page in a particular volume.
Paired genes from pairs of chromosomes is like page 67a/volume 23a with page 67b/volume 23b

The main themes of The Selfish Gene are:
(1) The gene is the unit of natural selection and survival; not the species as in Charles Darwin’s Theory of Evolution.  (2) Our bodies are just robotic survival machines created by our genes to house themselves (3) Each gene's sole purpose is to create as many copies of itself as possible in the universal gene pool of Life (4) We are hardwired by our genes (through brain, muscle and nervous system) to behave in ways that promote the gene's survival. Eating, choice of mate, fighting, greed, mothers' sacrifice for children, nepotism, grandparents' love of grandchildren, etc all have a gene-centric explanation.
How we behave and what we do is to a large extent ‘dictated’ by what would be the best option for the survival of our genes. And successful genes are those that score the highest points in terms of cost-benefit and resource maximization for the gene. All these complex game theory type of calculations are done unconsciously (instinctively) by the survival machine that houses the genes that is You.
Sounds like we are all servants of our genes who have taken over our body and manipulate us  for their own purpose.

No comments:

Post a Comment