SINE-derived satellites in scaled reptiles

Abstract

The genomes of many eukaryotes contain DNA repeats in the form of both tandem and interspersed elements with distinct structure, evolutionary histories, and mechanisms of emergence and amplification. Although there is considerable knowledge regarding their diversity, there is little evidence directly linking these two types. Different tandem repeats derived from portions of short interspersed elements (SINEs) belonging to different families were identified in 56 genomes of squamate reptiles. All loci of SINE-derived satellites (sSats) were thoroughly analyzed. Snake sSats exhibited high similarity in both structure and copy number, while other taxa may have highly diverse (geckos), rare (Darevskia lizards), or missing sSats (agamid lizards). Similar to most satellites associated with heterochromatin, sSats are likely linked to subtelomeric chromosomal regions. Discovered tandem repeats derived from SINEs exhibit satellite-like properties, although they have not amplified to the same degree as typical satellites. The autonomous emergence of distinct sSats from diverse SINE families in numerous squamate species suggests a nonrandom process of satellite genesis originating from repetitive SINEs.