Chromosome-Level Genome Assembly and Annotation of the Amur Rat Snake Elaphe schrenckii.

The Amur rat snake (Elaphe schrenckii), a widely distributed colubrid species in Northeast Asia, plays a critical role in controlling rodent and mouse populations in the wild. Despite its ecological and evolutionary significance, genomic resources for this nonvenomous species have been limited. In this study, we present a high-quality, chromosome-level genome assembly of E. schrenckii, generated by PacBio HiFi long-read sequencing and Hi-C chromatin interaction mapping. The assembled genome size comprises 1.69 Gb, with a scaffold N50 length of 215 Mb. Hi-C scaffolding anchored the genome into 18 chromosomes, including one that represents the conserved Z chromosome of snakes, consistent with karyotypic observations. This assembly enables further gene annotation and analysis of chromosomal synteny patterns. Repetitive elements account for 53.2% of the genome, with long interspersed nuclear element retrotransposons being the predominant class (23.2%). We identified 18,529 protein-coding genes, with 90.6% functionally annotated through homology-based methods. The genome assembly is highly complete, with a BUSCO score of 97.4% (tetrapoda_odb10). This resource provides a foundation for comparative studies of colubrid genome evolution, which also serves as a crucial reference for conservation genomics, particularly for Asian snake populations facing habitat fragmentation.