离子束重组酵母菌Han0458基因组重复序列的分布特征

Distribution Characteristics of Repeat Sequences in the Genome of the Yeast Recombinant Han0458 Obtained by Low-Energy Ion Beam Implantation

摘要: 重复序列是基因组的重要组成部分，对生物的进化、遗传和基因的表达调控有重要作用。为了进一步认识低能离子注入对酵母菌基因组结构的生物学效应，本研究利用生物信息学方法，在离子束重组酵母菌株Han0458全基因组de novo测序的基础上，对其基因组重复序列的分布特征进行了研究。结果表明，重组菌株Han0458基因组串联重复序列227,825 bp，散在重复序列107,439 bp，共占基因组长度的2.46%，重复序列在基因组中出现的频率为0.25个/Kb。微卫星DNA中重复单元拷贝数大多低于15次，其优势碱基类型为三碱基重复，重复单元基序为AAC的微卫星序列数目最多；小卫星DNA重复单元拷贝数小于微卫星DNA，主要分布1~3次，重复单元大于15 bp的小卫星序列数目随着重复单位长度的增加呈下降趋势。散在重复序列中长末端重复序列(LTR)数目最多，滚环(RC)平均长度最长。本研究结果为低能离子注入介导的酵母菌基因组突变与进化提供了分子证据。

Abstract: Repeat sequence is an important part of the genome and play an important role in the biological evolution, genetics, and regulation of gene expression. In order to further understand the biological effects of low-energy ion implantation on the yeast genome structure, in this study, we used bioinformatics methods to study the distribution characteristics of the genomic repeat sequences on the basis of de novo sequencing of the Han0458 genome. The results shows that the length of tandem repeats of the recombinant Han0458 genome is 227,825 bp and interspersed repeats is 107,439 bp, which account for 2.46% of the total genome length, and the frequency of repeats in the genome is 0.25 per Kb. The copy number of repeat units in microsatellite DNA are mostly less than 15 times, the dominant base type is trinucleotide repeats, and the number of microsatellite sequences with repeat unit motif AAC is the largest; the copy number of repeat units in minisatellite DNA is smaller than that of microsatellite DNA. The number of minisatellite DNA with a repeat unit greater than 15bp is decreasing with the increase of the repeat unit length. The number of long-terminal repeats (LTRs) is the largest in interspersed repeats, and the average length of rolling coils (RCs) is the longest. The results of this study provide molecular evidence for low-energy ion implantation-mediated yeast genome mutation and evolution.