BIODIVERSITY THROUGH THE EVOLUTION DRIVEN BY GENETIC MECHANISMS

The past concept of biodiversity was related to macroscopic phenotypic characteristics related to animals and plants in specific ecological systems, but it is important to underline that to this visible various universe there is a large influence from the microscopic more various universe of microorganisms. In addition genetic mechanisms are the base for the biodiversity of all living organisms from the smallest to the largest since the evolution derived from genetic changes and for this reason biodiversity is actually a never ending story with new species evolving and some old species disappearing to adapt to specific and continuouslychanging environments. Probably the variation among species was driven mostly by a subset of the variation withinspecies often caused by mutations in one gene resulting in its own loss of function. Additionally mutations contributing to phenotypic variation were often homologous across species, and tended to affect selected genes. Darwin’s lesson on the evolution of specieshas found the causative agent in nucleic acids, proteins, genomes and genetic variation through continuous but slow processes. The development of new genomic techniques, the rapid progress in molecular biology can help in identifying the sensible candidate genes for many phenotypic traits, for the optimal fitness and in some cases for disease resistance. All complex vegetal and animal species slowly evolved in specific various geographical areas / ecosystems during million years of evolution. Unfortunately human activity is heavily disturbing and often destroying many ecosystems with a great loss of the preexisting biodiversity. The genetic mutations necessary to adapt to new environments are very slow so the rapid environmental changes induced by human activity in the whole planet can bring to the rapid disappearance of several species with a dramatic reduction of biodiversity in all realms.  The preservation of biodiversity it is not only a prerogative for animals and plants into the wild but it is important also for the native domesticated animals and cultivated plants. The traditional agricultural and pastoral practices are specifically adapted to all different environments representing a cultural and historic background that should be preserved. Rural extensive animal breeding for example is often the main economic and nutritional recourse in marginal areas of the planet together with the harvest of comestible vegetables or the cultivation of small gardens and orchards. In developed countries the industrial methods (low cost with more productions and more profit) have been applied also in livestock managements and in the agricultural fields with the consequent diffusion of the highest productive animal breeds and vegetable cultivars with a consequent loss of the original biodiversity. But native breeds and cultivars are well adapted in specific ecosystems and should be well characterized both from the phenotypic and genotypic point of view to better realize their preservation.The studies on genetic polymorphisms can be important not only to distinguish the different species but also to characterize different breeds or cultivars within the same species. The identification and maintenance of genetic biodiversity can be important also to rise the economy of marginal areas.