Whole genome sequencing and phylogenetic analyses of the Sillaginidae family fish

For a long time, the taxonomic study of the Sillaginidae family of fish has been relatively slow, leaving the evolutionary relationships among species unclear. Previous research has mainly relied on morphological characteristics, with molecular studies limited primarily to mitochondrial genomics, including analyses of gene fragments and whole mitochondrial genomic sequence. This approach resulted in less precise and comprehensive species identification. In this study, we employed high-depth whole-genome sequencing (WGS) and genome surveys on 13 specimens representing 9 species of Sillaginidae fish collected from the wild. Our analysis included a thorough genomic survey and the assembly of draft genomes for each specimen. The genome sizes of Sillaginidae species are highly similar, ranging from 511.71 Mb to 578.27 Mb, with most individuals exhibiting repeat sequences content below 34.69 %. After the genome draft assembly of each sample, we identified conserved genes and shared consistent sequences among individuals and constructed a species phylogenetic tree based on these data. The results revealed that Sillago ingenua occupies the basal branch, followed by S. maculata and S. aeolus, then Sillaginopsis panijus, S. japonica and S. asiatica, and finally S. nigrofasciata and S. cf. sihama. Subsequently, we validated the phylogenetic tree using genome-wide single nucleotide variations, and the results were highly consistent. This research provides, for the first time, a whole-genome perspective on the evolutionary relationships among Sillaginidae species, offering valuable insights into their taxonomy and historical evolution.