Origins and Evolutionary Patterns of the Satellite DNA Family in Phylogeny.

Satellite DNAs (satDNAs) are a ubiquitous feature of eukaryotic genomes and are usually the major components of constitutive heterochromatin. The satDNA, also known as the 359 bp satellite, is one of the most abundant repetitive sequences in and has been linked to several different biological functions. We investigated the presence and evolution of the satDNA in 16 genomes. We find that the satDNA family is much more ancient than previously appreciated, being shared among part of the group that diverged from a common ancestor ∼27 Mya. We found that the satDNA family has two major subfamilies spread throughout phylogeny (∼360 bp and ∼190 bp). Phylogenetic analysis of ∼10,000 repeats extracted from 14 of the species revealed that the satDNA family is present within heterochromatin and euchromatin. A high number of euchromatic repeats are gene proximal, suggesting the potential for local gene regulation. Notably, heterochromatic copies display concerted evolution and a species-specific pattern, whereas euchromatic repeats display a more typical evolutionary pattern, suggesting that chromatin domains may influence the evolution of these sequences. Overall, our data indicate the satDNA as the most perduring satDNA family described in phylogeny to date. Our study provides a strong foundation for future work on the functional roles of satDNA across many species.