Sex-biased DNA methylation in small hive beetles (Aethina tumida)

DNA methylation is an important epigenomic modification that significantly influences various cellular and organismal functions. In this study, we investigate the methylome of the small hive beetle, Aethina tumida. Our analysis reveals an average of 58,306 CpG methylation marks per beetle, representing approximately 0.99% of the genome's total CpGs. Notably, 85.4% of these methylation marks are located within genic regions on autosomes, with similar rates observed in both male and female beetles. However, male beetles exhibit a lower number of methylation marks and upregulated genes on Chromosome X when compared to female beetles. To evaluate the impact of epialleles on methylation, we identified 5828 associations between SNPs and methylation, with genotypes accounting for 39.2% of the variation observed at highly methylated sites. Interestingly, unfertilised eggs display slightly higher levels of DNA methylation compared to adult beetles, whereas embryos show methylation levels that are only about half of those in adults. This suggests that DNA methylation is dynamic during early development.