THINKING ABOUT IMMENSE DIVERSITY IN NATURE. Part 1
HOW IS IT ACCOMPLISHED? WHAT IS ITS PURPOSE?
“The science of genetics is vitally important for all the life forms in the nature”.
I always wondered why is there so much diversity in nature in every life form, from single-cell organisms like viruses and bacteria to multiple cells organisms, animals, plants, trees, and the most sophisticated creatures like human beings? While I was searching for an answer to satisfy my curiosity and help me to understand the issue better, two especially important books attracted my attention. These books are The Gene, an intimate history by Dr. Siddhartha Mukherjee and, Human Diversity by Charles Murray.
Before I go any further, I would like to state that “how lucky we are, the nature is the way it is, otherwise, the sameness and monotony would have made our life unbearable and depressing.”
Maybe this is the main purpose of the nature to make our lives more interesting and challenging and quantifying the survival of the species. No wonder we often say that “mother nature knows best” and that “you cannot fool mother nature.”
The scientific advances in genetics have shown that the secret of biodiversity lies in the gene therefore, to better understand biodiversity, we must refresh our knowledge about the gene and genetics in a noticeably short and simple summary.
A gene is a biochemical compound that carries the units of heredity and instructions how to build, create and maintain different life forms in nature. It is composed of a stretch of DNA (deoxynucleic acid) that is present in double helix form of two complementary strands. Each strand of DNA is a chemical chain that is made up of four nucleic acids: A(alanine), T (thymine), G(guanine) and C (cytosine).
How genes are created remains a mystery in scientific circles, only theology explains it with Divine intervention and intelligent designs.
In humans, each strand of DNA consist of a string of more than three billion occurrence of one of the four nucleic acids and each strand is linked to a corresponding strand, in a strict order: A is always paired with T, and G is always paired with C.
Genes are housed in chromosomes of the nucleus of every cells. Human somatic cells have 46 (23 pairs) of chromosomes. In each pair, one chromosome comes from the mother, and the other from the father. Each pair of chromosomes contain 20 687 genes in humans.
Germ cells (egg and sperm) undergoes meiosis to reduce number of chromosomes into half.
Every cell also contains in their cytoplasm, several hundred subcellular structures called mitochondria. These minute structures are a kind of organic batteries and the source of vital energy production. Without them life is not possible. It is interesting to note that, only women possess mitochondrial genes, men do not.
Big apes, which are genetically very close to humans, have more 48 (24 pairs) of chromosomes. The number of genes also differ from species to species. Human genomes contain 20 687 genes which is only 1 796 genes more than earth warms, and 12 000 less then corn plants. From these scientific facts, it is not clear that only the quantity of the genes, but the quality and sophistication of the gene makes all the difference.
Most of the genes in human genome is not human et all. Some of the genes have been derived from the ancient viruses, embedded in and became part of the human DNA. We, as human share some genes from the immense gene pool that exist in the nature. How these multiple different genes spread across human genome, and how they coordinate their expression in time and space are not known to science.
Genes are dynamic, they are capable of reshuffling their genetic sequences to mutate and to make new variants of themselves, in response to internal or external stimulations to adapt or to overcome encountered difficulties and to evolve.
Genes can also change their functions, without changing their DNA sequences, just by making some chemical structures on their surfaces. Geneticists call this, beyond genetic, Epigenetics. Some of these chemical alterations could become heritable.
In conclusion, genes are capable of accommodating enough variants to create immense biodiversity, and make each of human beings unique, not only in size, in physical appearance, skin, hair and eye colors, but also in personality, intelligence, mental state and behaviors. Genes are the essence of biodiversity in nature.
