The Concept of Gene Flow - Essay Example

1. Population genetics has developed the concept of gene flow to represent the transfer of the DNA sequences of a gene from one population to another. Inside a species, it is the gene flow that somewhat repairs the genetic variations and provides uniformity for different populations of the same species. Thus the creation of offspring species is restricted. If there is an insurmountable physical barrier like a river or a mountain, populations of the same species on either side of this barrier will develop different genetic characteristics, through centuries of evolution.

Gene flow can happen either through hybridization or by the exchange of DNA sequences by bacteria or viruses. Bacteria and viruses have the ability to transfer genes across specie. The gene flow can also result in the formation of a combined gene pool that will have both the characteristics of the two population groups. Thus the barriers to gene flow, as well as the gene, flow itself, both have the potential to bring about species diversity and take evolution ahead. Genetic drift is the change in the frequency of a DNA sequence, usually called an allele.

This phenomenon totally depends on chance. When a new member is born in a species, the alleles that will be taken up into the genetic makeup of that individual will be through a process of random sampling. And if that individual lives enough to reproduce, only then there is an assurance that the specific alleles in his genes have a scope to survive. It is in this way that the allele frequency changes within a population and this leads to genetic variation within species. Thus a new generation may emerge which may either have lost one genetic trait or may have strengthened one genetic trait of the species, more visibly.

Mutations are sudden changes in the DNA sequence, of an organism, caused by many factors including, viruses, radiation, mutagenic chemicals, errors during DNA replication, transposition of DNA sequences within the genome, and errors in cell division while sexual reproduction. It has been proved that mutations have a great role in the process of evolution, that is, in the birth of new species, particularly, in smaller life forms like viruses and bacteria. But for higher life forms, mutations are harmful or neutral with respect to the survival of the species.

2. Race is a social construct rather than a scientific classification. All human beings belong to the species, Homo Sapiens. The concepts and categories of race have not been constant and these have been changing in the history of humankind. Scientists think the concept of race is unscientific, and not based on human biology. The genomic analyses have shown that there are no considerable genetic differences between different ‘races’, as conceived by Western common sense. The genome project has revealed that differences among individuals within a geographical population are 85% while the differences between individuals from two different geographical populations are only 15%.

This is clear evidence of the meaninglessness of the concept of 3 or 4 distinct races. The tracing back of human lineage to the eve DNA has proved that the ancestors of all the humans who inhabit the earth today, were a handful of humans who came out from Africa and spread all over the world. It is a proven fact that phenotypic variations, as is seen in the so-called different races, can be caused by environmental factors. Scientists have now proven beyond doubt that races are not equivalent to sub specie.

In a western country, ‘Indian’ can be considered as a race, but inside India, the ‘Hindus’ will consider ‘Muslims’ as a different race. So the division based on race is rather political and ideological rather than biological or genetic.