The Identification of Loci for Immune Traits in Chickens Using a Genome-Wide Association Study

Lei Zhang，Peng Li，Ranran Liu，Maiqing Zheng，Yan Sun，Dan Wu，Yaodong Hu，Jie Wen，Guiping Zhao*

1. Institute of Animal Science，Chinese Academy of Agricultural Sciences，Beijing，P.R. China，

2. Key Laboratory of Farm Animal Genetic Resources and Germplasm Innovation，Ministry of Agriculture，P.R. China，Beijing，P.R. China

通讯作者邮箱：zhaoguiping@caas.cn

The Identification of Loci for Immune Traits in Chickens Using a Genome-Wide Association Study

Lei Zhang1，2，Peng Li1，2，Ranran Liu1，2，Maiqing Zheng1，2，Yan Sun1，Dan Wu1，Yaodong Hu1，Jie Wen1，2，Guiping Zhao1，2*

1. Institute of Animal Science，Chinese Academy of Agricultural Sciences，Beijing，P.R. China，

2. Key Laboratory of Farm Animal Genetic Resources and Germplasm Innovation，Ministry of Agriculture，P.R. China，Beijing，P.R. China

通讯作者邮箱：zhaoguiping@caas.cn

学科：畜牧兽医

推荐专家：赵桂苹研究员（中国农业科学院北京畜牧兽医研究所）

推荐论文：Lei Zhang，Peng Li，Ranran Liu，et al. The Identification of Loci for Immune Traits in Chickens Using a Genome-Wide Association Study ［J］. PLoS One，2015，10（3）： e0117269

·专家点评·

首次系统、全面地对鸡的6个免疫形状指标（血清IgG、异嗜细胞数、淋巴细胞数、异嗜细胞和淋巴细胞比率、禽流感抗体滴度和绵羊红细胞抗体滴度）进行了GWAS分析，筛选出鸡16、19号等染色体免疫相关区域的重要候选基因，为深入探究家禽抗病免疫的机制以及重要基因的功能鉴定奠定了基础。

本研究新发现的位于鸡16号染色体狭窄区段（247kb）的5个候选基因（CD1b、 IL4I1、GNB2L1、TRIM27和ZNF692），与鸡抗病免疫密切相关。

The genetic improvement of disease resistance in poultry continues to be a challenge. To identify candidate genes and loci responsible for these traits，genome-wide association studies using the chicken 60k high density single nucleotide polymorphism（SNP）array for six immune traits，total serumimmunoglobulin Y（IgY）level，numbers of，and the ratio of heterophils and lymphocytes，and antibody responses against Avian Influenza Virus（AIV）and Sheep Red Blood Cell（SRBC），were performed. RT-qPCR was used to quantify the relative expression of the identified candidate genes. Nine significantly associated SNPs（P ＜ 2.81E-06）and 30 SNPs reaching the suggestively significant level（P ＜ 5.62E-05）were identified. Five of the 10 SNPs that were suggestively associated with the antibody response to SRBC were located within or close to previously reported QTL regions. Fifteen SNPs reached a suggestive significance level for AIV antibody titer and seven were found on the sex chromosome Z. Seven suggestive markers involving five different SNPs were identified for the numbers of heterophils and lymphocytes，and the heterophil/lymphocyte ratio. Nine significant SNPs，all on chromosome 16，were significantly associated with serum total IgY concentration，and the five most significant were located within a narrow region spanning 6.4kb to 253.4kb（P = 1.20E-14 to 5.33E-08）. After testing expression of five candidate genes（IL4I1，CD1b，GNB2L1，TRIM27 and ZNF692）located in this region，changes in IL4I1，CD1b transcripts were consistent with the concentrations of IgY，while abundances of TRIM27 and ZNF692 showed reciprocal changes to those of IgY concentrations. This study has revealed 39 SNPs associated with six immune traits（total serumIgY level，numbers of，and the ratio of heterophils and lymphocytes，and antibody responses against AIV and SRBC）in Beijing-You chickens. The narrow region spanning 247kb on chromosome 16 is an important QTL for serum total IgY concentration. Five candidate genes related to IgY level validated here are novel andmay play critical roles in themodulation of immune responses. Potentially useful candidate SNPs for markerassisted selection for disease resistance are identified. It is highly likely that these candidate genes play roles in various aspects of the immune response in chickens.

责任编辑：王帅帅