大鼠全基因组微卫星分布特征研究

摘要

Rat has been treated as a good model organism in studies on medicine and pharmacy.The ge-nome of Rattus norvegicus is the only sequenced mammal genome besides human and mouse.Microsatellites of the entire genome in R.norvegicus were searched using bioinformatics software in this study.A total of 1 483 525 simple sequence repeats( SSRs) with 1~6 bp nucleotide motifs were identified,occuping 1.41%of the genome.The highest frequency was observed in chromosome 12,followed by that in chromosome 10,and the lowest values of frequency was found in chromosome X.Highly positive correlation was observed between chro-mosome length and its SSR counts in the rat genome(r=0.978,P<0.000 1),reflecting random distribution of SSRs in R.norvegicus.The proportion of each type of SSRs from R.norvegicus genome was showed as follows:di-nucleotide(46.9%),monnucleotide(22.6%),tetranucleotide(17.7%),trinucleotide(8.4%),pentanucleotide (2.4%),hexanucleotide(2.0%).The dominant SSRs in monnucleotide,dinucleotide,trinucleotide,tetranucle-otide,pentanucleotide and hexanucleotide were A,AC,AGG,AAAC,AAACA and ACAGAG,respectively.The study provides the data support for SSRs selection and further research of the rat.%大鼠（ Rattus norvegicus）一直是医学和药学研究中良好的模式生物，其全基因组是继人和小鼠之后第3个被测定的哺乳动物。利用生物信息学软件对大鼠全基因组1～6 bp不同类型重复微卫星进行搜索及统计，表明大鼠全基因组微卫星序列共1483525个，其序列长度占全基因组的1．41％。大鼠全基因组微卫星分布频率以12号染色体最高，其次是10号染色体，最低的是X性染色体。大鼠微卫星数量与染色体DNA序列长度具有相关性（ r＝0．978，P＜0．0001），微卫星分布具有随机性。大鼠全基因组不同重复类型微卫星表现为二碱基（46．9％）＞单碱基（22．6％）＞四碱基（17．7％）＞三碱基（8．4％）＞五碱基（2．4％）＞六碱基（2．0％），单碱基、二碱基、三碱基、四碱基、五碱基、六碱基优势微卫星类型分别是A、AC、AGG、AAAC、AAACA、ACAGAG。本研究为大鼠全基因组微卫星筛选及进一步的研究提供数据支持。