Microsatellites are among the most versatile of genetic markers, being used in an impressive number of biological applications. However, the evolutionary dynamics of these markers and their function in genomes remain a source of contention. Almost 20 years after the discovery of these ubiquitous simple sequences, new genomic data are clarifying our understanding of the structure, distribution and variability of microsatellites in genomes, especially for the eukaryotes. We have recently reviewed(1) the mutational processes, biases and constraints believed to be involved in the evolution of microsatellites, particularly with respect to the creation and degeneration of microsatellites, which can be broadly viewed as a life cycle. We propose to test this concept in mammals using a blend of bioinformatics and comparative analysis above the species level. Our preliminary results unveil the unexpected extent of the conservation of microsatellite loci across mammalian species. We believe that analyses of variability of these conserved loci at the population level will provide invaluable information on the evolutionary course of microsatellites in eukaryotes and will be the ground for the development of a realistic model of evolution at these loci.

1. Buschiazzo, E and Gemmell, NJ (2006). The rise, fall and renaissance of microsatellites in eukaryotic genomes. BioEssays 28: 1040-1050.