Concerted Evolution of Genus-Specific Centromeric Satellite DNA in Eremias (Lacertidae, Reptilia)

Tandemly repeated satellite DNA sequences are an important part of animal genomes. They are involved in chromosome interactions and the maintenance of the integral structure of the nucleus, regulation of chromatin conformation and gene expression, and chromosome condensation and movement during cell division. Satellite DNAs located in the centromeric heterochromatin evolve rapidly and likely affect hybrid fertility and fitness. However, their studies are taxonomically highly biased. In lacertid lizards, satDNA has been extensively studied in the subfamily Lacertinae, but the subfamily Eremiadinae has been largely overlooked.

In this work, we describe a novel 177-bp-long centromeric satDNA family EremSat177, which is present in all studied species of the genus Eremias, but not in related genera. EremSat177 is not homologous to any previously identified centromeric satellites. Using fluorescence in situ hybridization, we demonstrate its centromeric localization in E. velox and E. arguta. We also show its tandem organization and intra-genomic homogenization by in silico analysis in the genome of E. argus. The phylogenetic analysis of consensus EremSat177 sequences from 12 Eremias species demonstrates that the same monomer subfamily is the most abundant in all these species, and its evolution mainly follows the species phylogeny as revealed by the mtDNA sequences.

The EremSat177 represents a novel, lineage-specific centromeric satellite DNA, and its role in centromere functioning should be revealed in further research.