小鼠血液中年龄相关的DNA甲基化微单倍型的筛选与验证

Screening and validation of age-related DNA methylation microhaplotypes in mouse blood

目的DNA甲基化微单倍型是指极短范围内多个甲基化位点的组合,其单倍型具有丰富的多样性。筛选和验证小鼠血液中年龄相关的DNA甲基化微单倍型。方法首先,构建基于小鼠参考基因组的DNA甲基化微单倍型理论数据集。其次,利用网络数据库中小鼠血液DNA甲基化高通量测序信息,采用Spearman秩相关分析方法筛选年龄相关的DNA甲基化微单倍型。最后,以验证数据集交叉验证。结果小鼠基因组中50 bp范围内的DNA甲基化微单倍型位点数量共计6787142个,由个位数的CpG位点所组成的DNA甲基化微单倍型占比98.64%。在58个小鼠血液样本中共筛选出5835个年龄相关的DNA甲基化微单倍型(Spearman秩相关检验,|rho|>0.5,P<0.01),在DNA甲基化微单倍型中占0.086%。最后,在95例独立的样本中对具有高相关性的前100个年龄相关的DNA甲基化微单倍型进行验证,最终得到44个位点。结论本研究筛选出的年龄相关的DNA甲基化微单倍型可以为后续小鼠血液表观年龄预测及衰老研究提供借鉴。

Objective The DNA methylation microhaplotype(DMH)refers to the combination of multiple methylation sites within a very short range,and these haplotypes show wide diversity.We carried out screening and validation of age-related DMHs in mouse blood.Methods We initially constructed a theoretical dataset of DMHs based on the mouse reference genome.We then screened age-related DMHs by Spearman’s rank correlation analysis,using highthroughput sequencing information for DNA methylation in mouse blood from a network database.Finally,cross-validation was performed using a validation dataset.Results A total of 6787142 DMH sites were identified within 50 bp in the mouse genome,including 98.64%of single-digit CpG sites.A total of 5835 age-associated DMHs were screened in 58 mouse blood samples(|rho|>0.5,P<0.01),accounting for 0.086%of DMHs.Finally,we validated the top 100 ageassociated DMHs with high correlation in 95 independent samples,Results ing in 44 loci.Conclusions The age-associated DMHs screened in this study may be useful in future studies of apparent age prediction using mouse blood and in aging studies.