Satellite DNA evolution in Tytonidae (Aves: Strigiformes): dynamic repeat landscapes despite conserved karyotypes

Abstract The elevated chromosome numbers observed in Tytonidae relative to the putative ancestral avian karyotype suggest that lineage-specific chromosomal fissions may have played an important role in the evolutionary history of this family. Here, we provide the first cytogenetic characterization of the American barn owl ( Tyto furcata ) and performs a comparative repeatome analysis across members of the Tytonidae, including other two species, the Western barn owl ( Tyto alba ), and the Oriental bay owl ( Phodilus badius ). The karyotype of T . furcata showed a 2n = 92, closely resembling that previously described for T . alba , indicating a high degree of chromosomal conservation within Tytonidae. Although T . furcata and T . alba exhibit similar karyotypic organization, comparative repeatomic analyses revealed differences in their composition, including variation in satellite DNA (satDNA) repertoires and abundance. Eight satDNA families were identified in T . furcata , nine in T . alba , and 28 in P . badius , highlighting the dynamic evolution of repetitive sequences. Several satDNA families were shared between T . furcata and T . alba , whereas some appeared species-specific, supporting the library hypothesis of satDNA evolution. In P . badius , multiple satDNAs exhibited similarity to transposable elements, suggesting that mobile elements contributed to their diversification. Cytogenetic analyses demonstrated centromeric heterochromatin distribution in T . furcata , as well as a large heterochromatic W chromosome enriched in DNA repeats. The localization of satDNAs in centromeric regions and the apparent accumulation of repeats on the W chromosome reinforce the role of repetitive sequences in chromosome organization and sex chromosome differentiation. Together, these findings reveal repeatome diversification despite conserved macrochromosomal structure and provide new insights into genome evolution and chromosomal dynamics in birds.