Genomic features of Hydrophis cyanocinctus and H. curtus. (a) Circos view of the genome assemblies (HCya_v2 and HCur_v2) of H. cyanocinctus and H. curtus. Tracks depict circular representation of haplotype chromosomes in megabases (Mb, a), GC percentage (b), the density of protein-coding genes, TEs, LTR elements (c–e), and gene expression profile of venom gland (f). Lines inside the circle indicate within-genome links between syntenic paralogs. (b) Bar plot comparing the genomic fractions of different classes of repeat elements and estimated genome size among six snakes. The repeat contents in the genomes of Naja naja, Ophiophagus hannah, Crotalus viridis, and Python bivittatus were retrieved from their publications (Castoe et al. 2013; Schield et al. 2019; Suryamohan et al. 2020). The assembly size of C. viridis genome (UTA_CroVir_3.0) was used as there had been no determined or estimated genome size reported for this species. (c) Violin plot showing the frequency distribution of sequence divergence between LTR pairs in the genomes of four snakes. Species name abbreviations: Hcya, H. cyanocinctus; Hcur, H. curtus; Nnaj, N. naja; Cvir, C. viridis; Ohan, O. hannah; Pbiv, P. bivittatus.