Contrasting Patterns of Differentiation Inferred from Traditional Genetic Markers in the Process of Speciation

Abstract

Populations of Drosophila serido from various geographic origins were characterized using four markers: morphology of male genitals, inversions in polytene chromosomes, morphology and heterochromatin of metaphase chromosomes, and reproductive isolation. In all cases the species shows itself to be polytypic, but the geographic distribution patterns vary according to the marker utilized. The validity of the use of these parameters for taxonomic purposes and/or for understanding the mechanisms involved in the differentiation among populations is discussed.