Magnitude of Human Genetic Variations: A Mini Review

Genetic variations are the genetic differences found among individuals of the same species. These variations are adaptive i.e. they ensure flexibility and survival of a population in the changing environment over time. It is quite interesting to know how and when these genetic variations offer to a population the survival benefit under the altered situations and at what extent over time. Whether there is any significant difference among male and female in expression of such variations. Further if the population subgroups and demographical factors offer any selective advantage to these variations. Moreover we often find that one drug which is effective on an individual may not work well with other individual. This interindividual variation of drug effects is due to the genetic variation of drug metabolism. The variations of xenobiotic or drug metabolizing enzymes at genetic level bring about the evolution of diverse and specific subgroups in the population that offers a selective ability to perform the biotransformation reactions. With the advent of advance DNA sequencing technologies we are now able to find and characterize most of the natural variations such as single nucleotide polymorphisms, structural variations like insertion/deletion, inversion, translocations, tandem repeat polymorphism, complex chromosomal rearrangements etc. that are linked with human evolution, migration, disease susceptibility, adaptation to divers geographical regions etc. This mini review focus on basic genetic variations and their possible associations with human health, forensics, environmental stress management, various diseases and other relevant aspects.