Caracterização in silico do satelitoma e mitogenoma de Alagoasa pantina Bechyne, 1958 (Coleoptera, Alticini)

Abstract

The genomes of eukaryotic organisms contain repetitive sequences that can be either dispersed or organized in tandem. The latter category includes satellite DNAs (satDNAs), which are major components of heterochromatin and are involved in several functions such as chromosome segregation, centromere structuring, kinetochore assembly, and chromosome pairing during meiosis. Recent studies suggest that the accumulation and amplification of satDNAs are associated with the evolution and differentiation of sex chromosomes. Accordingly, these sequences may be linked to the presence of giant and asynaptic sex chromosomes observed in the subtribe Oedionychina (Alticini, Chrysomelidae). These features have been extensively discussed in species of the genus Alagoasa, yet only one Alticini species has been characterized in terms of its satellitome in the literature. Therefore, this study aimed to characterize the set of satDNAs and describe the mitogenome of Alagoasa pantina.The satellitome data were processed using the Tandem Repeat Analyzer (TAREAN) platform, integrated into RepeatExplorer2, following the SatMiner pipeline. The mitogenome was assembled using GetOrganelle, with Omophoita sp. as a reference, and annotated on Proksee using the MITOS2 tool. The diploid genome size of A. pantina was estimated at approximately 4.54 Gb in females and 4.24 Gb in males. Within this genome, satDNA constitutes a significant fraction, comprising 87 distinct families present in both sexes. SatDNA content represents 8.70% of the female genome and 9.52% of the male genome, corresponding to approximately 395 Mb in females and 404 Mb in males. The repeat unit lengths (RULs) for these families range from 4 bp to 4,070 bp, with a median of 425 bp. Most of these families exhibit high A+T content, with a median of 63.42%, suggesting a bias toward A+T-rich sequences. Furthermore, comparative analysis between sexes revealed differences in satDNA abundance, with three families enriched in males and four in females. These differences may be associated with the sex chromosomes, suggesting that these satDNA families are sex-specific and may play a role in their differentiation.In addition to satellitome characterization, the mitochondrial genome assembly of A. pantina resulted in a circular double-stranded molecule of 15,636 bp, containing 35 functional genes and two non-coding regions. The results provide new insights into the genomic organization of A. pantina, both in terms of its repetitive DNA fraction and mitochondrial genome structure.