Structural Features and Mitogenome-Based Evolutionary In-sights into Acanthopleura loochooana
Next-generation sequencing was performed by Novogene Co., Ltd. A paired-end library was constructed using the Illumina TruSeq DNA Sample Preparation Kit and sequenced on the Illumina NovaSeq 6000 platform, generating 150 bp paired-end reads. The sequencing data showed high quality, with a Q30 ratio above 90%, and provided sufficient depth for mitochon-drial genome assembly. Raw read quality was assessed using FastQC v0.11.5, and adapter se-quences and low-quality reads were removed using fastp v0.23 [26]. The filtered reads were as-sembled into the complete mitochondrial genome using GetOrganelle v1.7.5.0 with a k-mer size of 31. Default parameters were used for all other settings. Circularization of the mitogenome was first assessed during the assembly process and then verified by examining terminal overlap consistency, completeness of the mitochondrial gene set, and the correctness of start and stop codons in protein-coding genes. Genome annotation was performed using the MITOS2 online tool (https://usegalaxy.org/) [27] under the invertebrate mitochondrial genetic code.