Quantifying genetic diversity: the starting point for population genetic studies using molecular markers

Abstract

Natural populations must keep genetic diversity since it is essential for the long-term survival of species and provides the raw material for all evolutionary changes.The emergence of marker systems has, for the last 40 years, closely tracked developments in biochemistry and molecular biology. Morphological markers were largely supplanted by biochemical markers and the latest markers were supplanted by the development of markers based on DNA polymorphisms. A molecular marker is in essence a nucleotide sequence corresponding to a particular known or unknown physical location in the genome.Genetic diversity represents the total genetic variation among individuals within a population. Over the years an evolution in the understanding of genetic diversity quantification can be perceived. In order to know the evolution in this understanding we surveyed the archives of the prestigious scientific journal Heredity. Population genetics was born mainly as a theoretical science. Protein electrophoresis produced data that could be interpreted using the language and perspective of traditional population genetic theory and it allowed that population genetic become in an empirical science. The field of empirical population genetics started to be preoccupied with characterizing and quantifying genetic variation. Now this view is evolving and the impact of population genetics increased considerably in almost all fields of biology. We could conclude that estimation of genetic diversity was the goal of several studies per se twenty years ago. However, quantification of genetic diversity is nowadays an obligatory step in population genetic studies regardless of the main aim of these studies.