Population genetics is rapidly changing driven by the advances in modern molecular technologies. The sheer volume of data being generated is allowing empirical studies until just recently confined to the realm of theory while simultaneously prompting the need to develop new computational approaches to data storage and analysis. Theoretical contributions, as Kimura's neutralism and subsequent theories are expanding the scope of this discipline beyond its traditional subject matter. Besides gene frequencies and evolutionary "forces", it is incorporating new elements, such as molecular phylogeny. In this context, population genetics is coming closer to historical and comparative biology and changing our comprehension of its role in the evolutionary process.