Individuality and the Genome

UNDERSTANDING INDIVIDUALITY: 

Dr. Michael Elowitz, Physicist at California Institute of Technology has conducted experiments on colonies of genetically identical (Clones) E. coli bacteria under identical experimental conditions and has discovered that the clones behave in different ways which could be viewed as an expression of ‘individuality’.

E. coli bacteria in billions populate our intestines. Typical E. coli bacillus has about 4,000 genes. Human cells have about 20,000 genes. The bacteria have fingerprints of their own and even when they share the exact same genome, they could still be identified as ‘individuals’.

The key to understanding E. coli’s fingerprints is to recognize that the bacteria are not simple machines. Unlike wires and transistors, E. coli’s molecules are floppy, twitchy and unpredictable. In an electronic device, like a computer or a radio, electrons stream in a steady flow through the machine’s circuits, but the molecules in E. coli jostle and wander. When E. coli begins using a gene to make a protein, it does not produce a smoothly increasing supply. It spurts out the proteins in fits and starts. One clone may produce half a dozen copies of a protein in an hour, while a clone right next to it produces none.

Michael Elowitz, a physicist at Caltech, put these bursts on display in an elegant experiment. He and his colleagues incited E. coli to produce its proteins for feeding on lactose. Dr. Elowitz and his colleagues added extra genes to the bacteria so that when they made lactose-digesting proteins, they also released light.

The bacteria, Dr. Elowitz found, did not produce a uniform glow. They flickered, sometimes brightly, sometimes dimly. And when Dr. Elowitz took a snapshot of the colony, it was not a uniform sea of light. Some microbes were dark at that moment while others shone at full strength.

At the very least, E. coli’s individuality should be a warning to those who would put human nature down to any sort of simple genetic determinism. Living things are more than just programs run by genetic software. Even in minuscule microbes, the same genes and the same genetic network can lead to different fates.

The bacteria have fingerprints of their own and even when they share the same genome, they could still be identified as individuals.

Humans differ from one another in too many different ways and it is hard to count. The current human population of over six billion could be identified as the same number of individuals. Each human being has an unique genome of his own. There are millions of typographical differences between one genome and another human genome. Even identical twins are not truly identical at all as identical genes in our cells can behave differently. 

Living entities are not like simple machines. When we use a gene to make a protein, the gene may not produce a smoothly increasing supply of that protein. The gene tends to work in fits and starts and spurts out the protein. Identical genes can behave differently as the gene makes protein or remains silent depending upon the ‘Methyl’ groups that cap the DNA strands and function as ‘transducers’. These ‘Methyl’ groups sometimes fall off of DNA or become attached to new spots. Hence genetically identical individuals can have different physical identities in the natural world. The protein molecules that make up living entities, turn them into individuals. 

THE IRRELEVANCE OF EVOLUTION: 

In the natural world, all living entities exist as individuals and express their individuality. The Theory of Evolution proposes that a species can descend or arrive to become a new species by changing its genome in a gradual and incremental manner using a mechanism that is described as ‘ natural selection ‘. The mechanism of natural selection operates via a process of random and unguided mutations in the genetic code that changes the genome and eventually produces the ‘biodiversity’ that we witness in the natural world.

This Theory of Evolution has no relevance to the ultimate identity of each individual member of a given species. This identity is dictated by the interplay between the various components of each individual cell and its interactions with other cells. With the same genomes or different genomes, the living entities can only exist as individuals and they have no other choice. The evolutionary connections are not relevant to this identity. To understand the phenomenon of biodiversity, we will be forced to look at each individual member of each given species. 

THE LAW OF INDIVIDUALITY: 

I propose that the Law of Individuality governs all the living entities and is manifested in various biological phenomena. The genes and the genetic code function in accordance with the Law of Individuality. I would describe Individuality as a Trade Mark. It is the characteristic of a biological entity. Genes and the genetic codes are the tools that an organism uses to express its Individuality. Each organism assembles its own kind of protein molecules to define its identity and to defend its existence in the natural world.