<b>Comparative Genomics Unveils Unique Antithrombotic Gene Expansion in </b><b><i>Haemadipsa yanyuanensis</i></b>

Haemadipsa yanyuanensis is a terrestrial blood-feeding leech with underexplored anticoagulant adaptations. Here, we present its first chromosome-level genome assembly (165.32 Mb, 9 chromosomes; BUSCO completeness: 97.6%) generated using Nanopore, Hi-C, and RNA-seq data. We identified 193 antithrombotic genes across 15 families, representing a 2.2- to 2.7-fold increase in gene number but a reduction in gene family diversity compared to aquatic medicinal leeches (Hirudo medicinalis, Hirudinaria manillensis, and Hirudo nipponia). Notably, bdellin, LDTI, and LCI gene families exhibited large-scale expansions ranging from 8.7- to 25-foldcompared to aquatic leeches. while the progranulin gene exhibited a lineage-specific structure with 122 cysteine residues and nine tandem repeats. Transcriptomic profiling revealed high expression of these expanded families, suggesting their pivotal role in terrestrial blood-feeding adaptation. Our study reveals a novel gene family expansion-contraction model for antithrombotic evolution. These unique genomic data provide a new resource for the development of next-generation anticoagulant drugs.Supplementary File_S1_genome. fa: Genome assembly of H. yanyuanensis;Supplementary File_S2_all_CDS. fa: CDSs of all predicted protein-coding genes;Supplementary File_S3_antithrombotic_CDS. fa: CDSsof 193antithrombotic genes;Supplementary Figures_S1 to S14. docx: Sequence alignments of antithrombotic protein families not shown in the main text.盐源山蛭（Haemadipsa yanyuanensis）是一种陆生吸血蚂蟥，其抗凝适应机制尚未得到充分探索。本研究首次报道了基于纳米孔（Nanopore）测序、Hi-C及RNA-seq数据组装的该物种染色体水平基因组（基因组大小165.32 Mb，包含9条染色体；通用单拷贝同源基因基准评测（BUSCO）完整度为97.6%）。我们在15个基因家族中鉴定出193个抗血栓基因，相较于水生药用蚂蟥（欧洲医蛭Hirudo medicinalis、菲牛蛭Hirudinaria manillensis、日本医蛭Hirudo nipponia），该物种的抗血栓基因数量增加了2.2~2.7倍，但基因家族多样性却有所降低。值得注意的是，山蛭素（bdellin）、水蛭源性胰蛋白酶抑制剂（LDTI）及水蛭几丁质酶抑制剂（LCI）基因家族相较于水生蚂蟥发生了大规模扩张，扩张幅度达8.7~25倍；而颗粒蛋白前体（progranulin）基因具有谱系特异性结构，包含122个半胱氨酸残基与9个串联重复序列。转录组表达谱分析显示，这些扩张的基因家族呈现高表达水平，表明其在陆生吸血适应过程中发挥关键作用。本研究揭示了一种全新的抗血栓进化基因家族扩张-收缩模型。这批独特的基因组数据为新一代抗凝药物的开发提供了全新的研究资源。 补充文件_S1_genome.fa：盐源山蛭基因组组装序列； 补充文件_S2_all_CDS.fa：所有预测蛋白编码基因的编码序列（CDS）； 补充文件_S3_antithrombotic_CDS.fa：193个抗血栓基因的编码序列（CDS）； 补充图_S1至S14.docx：正文未展示的抗血栓蛋白家族序列比对结果。