Genetic Remembering

December 29th, 2006 Fred McVittie

Although the ‘human genome’ is referred to in the media and popular press as if it were a single, universal component of all human beings, there is variation in this genome across different members of the human race; variation which accounts for the different ways in which the being of human is expressed by different individuals. Nevertheless, the percentage of common genetic material is well above 99% and it is this common material which gives us our similarities and, ultimately, accounts for the universalities which exist. We also have much in common, genetically, with non-human animals; with primates this percentage is also in the high 90’s. Even creatures with whom we may choose not to identify, lobsters or snakes for example, share over 50% of our DNA, and so can be considered distant relatives, and this also goes for every living thing on Earth.

The evolutionary process can be considered as a kind of remembering, in which the good ideas of past generations, i.e. those which confer a survival advantage, are passed on to future generations. These memories live on in our bodies in the form of opposable thumbs, thickened skin on the soles of our feet, binocular vision, etc. They also live on in our minds as drives, instincts, reflexive responses, and emotions. These psychic memories helped our ancestors to survive and they now form the basic architecture of our thoughts and actions.

Posted in Evolution, Genetics, Memory | No Comments »

A Gene’s Eye View

January 30th, 2008 Fred McVittie

It has been estimated that the human genome contains around 24.000 different protein-encoding genes, which are the key carriers of the information which constitutes the ‘recipe’ for human life. This number is considerably less than was originally estimated and demonstrated the versatility and combinatorial power of these relatively few building blocks.

Of these 24,000, the vast majority are found in all human beings, with only a few minor variants effecting the genetic differences between individuals and groups. The amount of genetic information shared by every person on Earth is around 99.99%. In addition to this, the majority of this gene pool is not only flowing through humans but also through the phylogeny of animals and non-animal lifeforms; primates share somewhere in the region of 97% of our genes, lobsters and spiders around 70%, bananas between 50 and 60%, and yeast has about 30% of its genes in common with our own.

In addition to the genes found only in humans, there must be many more which code for non-human features of other lifeforms; the wings of birds and insects, the carapace of a tortoise, the compound eye of fly, the spinneret of a spider. Let’s say that the total number of genes found everywhere in the any kind of lifeform at any one time in history is 100,000.

It is reckoned that there are between 1.4 and 1.5 million named species of lifeform on the planet, but this number reflects only a small percentage of the actual number, which has been estimated in excess of 10 million. In addition, the division of life into species is not an exact science and does not reflect the distribution and multiplicity of genetic orderings that actually take place, or the changes that have occurred in that ordering in the past. The 100,000 characters in the total gene pool have been assembled into many more sentences than any of these numbers suggest. So this comparatively small number of genes is spread out across a vast spectrum of animal and plant life, each gene threading its way across species boundaries, sometimes spanning the globe and taking up residence everywhere and in everything, and sometimes confining itself to small niches of existence. The cell wall is a physical structure found in almost all lifeforms, and the gene sequence which contributes to the formation of this structure covers the globe. One vast pulsing gene being whose natural environment is the body of every living thing on the planet. The gene sequences for less distributed or more ideosyncratic features, opposable thumbs, toxic skin, night vision, consciousness, occupy only limited regions within this living landscape. Sometimes these tiny communites of genetic expression take hold within their environment, spill out of their niche, and spread through the time and space of the living world.

Posted in Evolution, Genetics, Space, Time | No Comments »