Data from: Genome-wide association study of insect bite hypersensitivity in Swedish-born Icelandic horses

Insect bite hypersensitivity is the most common allergic skin disease in horses and is caused by biting midges, mainly of the genus Culicoides. The disease predominantly comprises a type I hypersensitivity reaction, causing severe itching and discomfort that reduce the welfare and commercial value of the horse. It is a multifactorial disorder influenced by both genetic and environmental factors, with heritability ranging from 0.16 to 0.27 in various horse breeds. The worldwide prevalence in different horse breeds ranges from 3% to 60%; it is >50% in Icelandic horses exported to the European continent and approximately 8% in Swedish-born Icelandic horses. To minimize the influence of environmental effects, we analyzed Swedish-born Icelandic horses to identify genomic regions that regulate susceptibility to insect bite hypersensitivity. We performed a genome-wide association study on 104 affected and 105 unaffected Icelandic horses genotyped using Illumina® EquineSNP50 Genotyping BeadChip. Quality control and population stratification analyses were performed with the GenABEL package in R (lambda = 0.81). The association analysis was performed using the Bayesian variable selection method, Bayes C, implemented in GenSel software. The highest percentage of genetic variance was explained by the windows on chromosomes X (0.51% and 0.36% by 73 and 74 Mb), 17 (0.34% by 77 Mb), and 18 (0.34% by 26 Mb). Overlapping regions with previous GWA studies were observed on chromosomes 7, 9, and 17. The windows identified in our study on chromosomes 7, 10, and 17 harbored immune system genes and are priorities for further investigation.昆虫叮咬超敏反应（Insect bite hypersensitivity）是马类最常见的过敏性皮肤病，主要由蠓属（Culicoides）昆虫的叮咬引发。该疾病主要为I型超敏反应（type I hypersensitivity），会引发严重瘙痒与不适，进而降低马匹的福利水平与商业价值。其属于多因子失调性疾病，受遗传与环境因素共同影响，不同马品种的遗传力范围为0.16至0.27。全球范围内不同马品种的患病率介于3%至60%之间；出口至欧洲大陆的冰岛马患病率超过50%，而瑞典本土繁育的冰岛马患病率约为8%。为尽可能降低环境因素的干扰，本研究选取瑞典本土繁育的冰岛马作为研究对象，以鉴定调控昆虫叮咬超敏反应易感性的基因组区域。本研究针对104例患病冰岛马与105例健康对照冰岛马开展全基因组关联分析（genome-wide association study），所有样本均通过Illumina® EquineSNP50基因分型芯片完成基因分型。本研究使用R语言的GenABEL软件包开展质量控制与群体分层分析（λ=0.81）。关联分析则采用GenSel软件中实现的贝叶斯变量选择方法Bayes C完成。遗传方差解释率最高的基因组窗口位于X染色体（73 Mb与74 Mb区间分别解释0.51%与0.36%的遗传方差）、17号染色体（77 Mb区间解释0.34%）与18号染色体（26 Mb区间解释0.34%）。7号、9号与17号染色体上存在与既往全基因组关联研究重合的区域。本研究在7号、10号与17号染色体上鉴定到的基因组窗口携带有免疫相关基因，可作为后续研究的重点方向。