ABSTRACT
INTRODUCTION: Eukaryotic genomes are composed of simple, repetitive sequences, including satellite DNAs (satDNA), which are noncoding sequences arranged in tandem arrays. These sequences play a crucial role in genomic functions and innovations, influencing processes such as the maintenance of nuclear material, the formation of heterochromatin and the differentiation of sex chromosomes. In this genomic era, advances in next-generation sequencing and bioinformatics tools have facilitated the exhaustive cataloging of repetitive elements in genomes, particularly in non-model species. This study focuses on the satDNA content of Ancistrus sp., a diverse species of fish from the Loricariidae family. The genus Ancistrus shows significant karyotypic evolution, with extensive variability from the ancestral diploid number. METHODS: By means of bioinformatic approaches, 40 satDNA families in Ancistrus sp., constituting 5.19% of the genome were identified. Analysis of the abundance and divergence landscape revealed diverse profiles, indicating recent amplification and homogenization of these satDNA sequences. RESULTS: The most abundant satellite, AnSat1-142, constitutes 2.1% of the genome, while the least abundant, AnSat40-52, represents 0.0034%. The length of the monomer repeat varies from 16 to 142 base pairs, with an average length of 61 bp. These results contribute to understanding the genomic dynamics and evolution of satDNAs in Ancistrus sp. CONCLUSION: The study underscores the variability of satDNAs between fish species and provides valuable information on chromosome organization and the evolution of repetitive elements in non-model organisms.
ABSTRACT
Among the repetitive elements, satellite DNA (SatDNA) emerges as extensive arrays of highly similar tandemly repeated units, spanning megabases in length. Given that the satDNA PboSat01-176, previously characterized in P. boiei, prompted our interest for having a high abundance in P. boiei and potential for centromeric satellite, here, we employed various approaches, including low coverage genome sequencing, followed by computational analysis and chromosomal localization techniques in four Proceratophrys species and, investigating the genomic presence and sharing, as well as its potential for chromosomal centromere marker in Proceratophrys frog species. Our findings demonstrate that PboSat01-176 exhibits high abundance across all four Proceratophrys species, displaying distinct characteristics that establish it as the predominant repetitive DNA element in these species. The satellite DNA is prominently clustered in the peri/centromeric region of the chromosomes, particularly in the heterochromatic regions. The widespread presence of PboSat01-176 in closely related Proceratophrys species reinforces the validity of the library hypothesis for repetitive sequences. Thus, this study highlighted the utility of the satDNA family PboSat01-176 as a reliable centromeric marker in Proceratophrys species, with potential to be applied in other species of anuran amphibians. The observed sharing and maintenance of this sequence within the genus suggest possibilities for future research, particularly through expanded sampling to elucidate parameters that underlie the library hypothesis and the evolutionary dynamics of satDNA sequences.
