Slow Rates of Evolution and Sequence Homogenization in an Ancient Satellite DNA Family of Sturgeons

Satellite DNA sequences are noncoding, short, tandemly repeated sequences located mainly at centromeres and telomeres (Charlesworth, Sniegowski, and Stephan 1994 ). The main concerns of evolutionary patterns of satellite DNA sequences are their rapid change rate and their concerted mode of evolution. When a satellite DNA family is shared by several related species, this enables one to find specific diagnostic sites for use in phylogenetic studies (Arnason, Grettarsdottir, and Widegren 1992 ; Gretarsdottir and Arnason 1992 ). Here, we analyze an exceptional ancient satellite DNA family of sturgeons which does not fit the evolutionary features of most satellite DNAs. Specifically, we found that the evolution of this satellite DNA family is very slow, as reflected by low mutation and homogenization rates. Notwithstanding, our data offer some information on the tracing of mechanisms accounting for the formation and origin of this satellite DNA family and on the phylogeny of the sturgeons.