Equine insect bite hypersensitivity (IBH) is a pruritic skin allergy caused primarily by biting midges, Culicoides spp. IBH susceptibility has polygenic inheritance and occurs at high frequencies in several horse breeds worldwide, causing increased costs and reduced welfare of affected horses. The aim of this study was to identify and validate single nucleotide polymorphisms (SNPs) associated with equine IBH susceptibility. After quality control, 33,523 SNPs were included in a Bayesian genome-wide association study on 177 affected and 178 unaffected Icelandic horses. We report associated regions in E. caballus (ECA) 1, 3, 15 and 18, overlapping with known IBH QTLs in horses, and novel regions containing several genes, together explaining 11.46% of the total genetic variance. For validation, three SNPs on ECA 1 and ECA X (explaining the largest percentage of genetic variance) within 1-mb genomic windows for IBH were genotyped in an independent population of 280 Exmoor ponies. The associated genomic region (152-153 mb) on ECA 1 was confirmed in Exmoor ponies and contains the AQR gene involved in splicing processes and a long non-coding RNA. This study confirms the polygenic nature of IBH susceptibility and suggests a role of transcriptional regulatory mechanisms (e.g., alternative splicing) for IBH predisposition in these horse breeds.

中文翻译：

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马昆虫叮咬过敏易感性的全基因组关联研究揭示了 1 号染色体上的新相关位点

马昆虫叮咬过敏症 (IBH) 是一种瘙痒性皮肤过敏症，主要由叮咬蠓类（Culicoides spp）引起。IBH 易感性具有多基因遗传性，并且在世界范围内的几个马品种中发生频率很高，导致受影响马的成本增加和福利降低。本研究的目的是鉴定和验证与马 IBH 易感性相关的单核苷酸多态性 (SNP)。经过质量控制，33,523 个 SNP 被纳入贝叶斯全基因组关联研究，研究对象为 177 匹受影响和 178 匹未受影响的冰岛马。我们报告了 E. caballus (ECA) 1、3、15 和 18 中的相关区域，与马中已知的 IBH QTL 重叠，以及包含多个基因的新区域，共同解释了总遗传变异的 11.46%。为了验证，在 280 只 Exmoor 小马的独立种群中，对 IBH 1-mb 基因组窗口内的 ECA 1 和 ECA X 上的三个 SNP（解释了最大百分比的遗传变异）进行了基因分型。ECA 1 上的相关基因组区域 (152-153 mb) 在 Exmoor 小马中得到证实，并包含参与剪接过程的 AQR 基因和长非编码 RNA。这项研究证实了 IBH 易感性的多基因性质，并表明转录调控机制（例如，选择性剪接）对这些马品种的 IBH 易感性的作用。