Yan Yiyuan, Yi Guoqiang, Sun Congjiao, Qu Lujiang, Yang Ning
Department of Animal Genetics and Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China.
PLoS One. 2014 Aug 18;9(8):e104652. doi: 10.1371/journal.pone.0104652. eCollection 2014.
Insertion and deletion (INDEL) is one of the main events contributing to genetic and phenotypic diversity, which receives less attention than SNP and large structural variation. To gain a better knowledge of INDEL variation in chicken genome, we applied next generation sequencing on 12 diverse chicken breeds at an average effective depth of 8.6. Over 1.3 million non-redundant short INDELs (1-49 bp) were obtained, the vast majority (92.48%) of which were novel. Follow-up validation assays confirmed that most (88.00%) of the randomly selected INDELs represent true variations. The majority (95.76%) of INDELs were less than 10 bp. Both the detected number and affected bases were larger for deletions than insertions. In total, INDELs covered 3.8 Mbp, corresponding to 0.36% of the chicken genome. The average genomic INDEL density was estimated as 0.49 per kb. INDELs were ubiquitous and distributed in a non-uniform fashion across chromosomes, with lower INDEL density in micro-chromosomes than in others, and some functional regions like exons and UTRs were prone to less INDELs than introns and intergenic regions. Nearly 620,253 INDELs fell in genic regions, 1,765 (0.28%) of which located in exons, spanning 1,358 (7.56%) unique Ensembl genes. Many of them are associated with economically important traits and some are the homologues of human disease-related genes. We demonstrate that sequencing multiple individuals at a medium depth offers a promising way for reliable identification of INDELs. The coding INDELs are valuable candidates for further elucidation of the association between genotypes and phenotypes. The chicken INDELs revealed by our study can be useful for future studies, including development of INDEL markers, construction of high density linkage map, INDEL arrays design, and hopefully, molecular breeding programs in chicken.
插入缺失(INDEL)是导致遗传和表型多样性的主要事件之一,但其受到的关注少于单核苷酸多态性(SNP)和大结构变异。为了更好地了解鸡基因组中的INDEL变异,我们对12个不同鸡品种进行了新一代测序,平均有效深度为8.6。获得了超过130万个非冗余短INDEL(1 - 49 bp),其中绝大多数(92.48%)是新发现的。后续验证试验证实,随机选择的INDEL中大多数(88.00%)代表真实变异。大多数INDEL(95.76%)小于10 bp。缺失的检测数量和受影响的碱基都比插入的多。INDEL总共覆盖3.8 Mbp,占鸡基因组的0.36%。估计平均基因组INDEL密度为每千碱基0.49个。INDEL普遍存在且在染色体上分布不均匀,微小染色体中的INDEL密度低于其他染色体,一些功能区域如外显子和非翻译区(UTR)比内含子和基因间区域更容易出现较少的INDEL。近620,253个INDEL位于基因区域,其中1,765个(0.28%)位于外显子中,跨越1,358个(7.56%)独特的Ensembl基因。其中许多与经济重要性状相关,有些是人类疾病相关基因的同源物。我们证明,中等深度对多个个体进行测序为可靠鉴定INDEL提供了一种有前景的方法。编码INDEL是进一步阐明基因型与表型之间关联的有价值候选对象。我们研究中揭示的鸡INDEL可用于未来的研究,包括开发INDEL标记、构建高密度连锁图谱、设计INDEL阵列,有望用于鸡的分子育种计划。