During the last two decades the role of genetics in conservation biology, and ecology in general, has been greatly emphasised.  The assessment of genetic diversity in (endangered) animal and plant populations, either if natural or captive, wild or domesticated, is now pervasive.  Such a process, and progress, is driven by technical, conceptual and socio-economical reasons, as well.  Powerful methods for DNA analyses are being increasingly used to estimate the extent and organisation of genetic diversity in populations, to infer the causes of its spatio-temporal dynamics and to suggest strategies for conservation and the wise use of genetic resources.  In this sense, in a period of dramatic human exploitation and consumption of natural biological resources and concomitant development of biotechnologies, the emerging field of conservation genetics can help to guide the necessary harmony between economic development and nature preservation.  Conservation genetics hence provides important tools for the assessment of biodiversity according to the biodiversity convention of the United Nations (Rio convention).