基于高通量测序的思茅松微卫星位点的特征分析

Characteristic analysis of microsatellite in Pinus kesiya var. langbianensis by using high-throughput sequencing

以思茅松针叶为材料,采用Illumina Hiseq2000平台测序,得到121 882条无冗余的序列,对这些序列进行SSR位点搜索,共获得3534个SSR位点,出现频率为2.9%,分布平均距离25kb。所搜索的SSR以单核苷酸重复类型最多,其次为三核苷酸和二核苷酸,而四、五、六核苷酸重复类型较少(<1%)。单核苷酸重复类型中以A/T基元较丰富(43.58%);二核苷酸中出现频率最高的是AT/TA基元(14.04%),AG/CT次之,AC/GT和CG/CG较低;三核苷酸重复类型中AAG/CTT最多,AGC/CTG和AGG/CCT次之,以CCG/CGG、ACG/CGT和ACT/AGT较少(<1%);四、五、六核苷酸类型中各重复基元相差不大,均较少。SSR数量随对应的重复类型重复次数的增加而降低,也随重复区段碱基长度的增加而降低。

Needle sample of Pinus kesiya var. langbianensis was sequenced with high-throughput sequencing technology （Illumina Hiseq 2000）. In total 121 882 transcripts of Pinus kesiya var. langbianensis. were screened using MISA software. 3534 SSRs were identified, and the frequency of SSR was 2.9% and mean distribution density was 25 kb. The mono-nucleotide repeats were the highest, followed by tri-nucleotide and di-nucleotide repeat types. The tetra-nucleotide, petra-nucleotide and hexa-nucleotide were all less than 1%. Among the mononucleotide repeats, the A/T repeats motifs were the highest frequency （43.58%）. AT/AT was the most frequent repeat motifs in di-nucleotide repeats （14.04%）, followed by AG/CT. AC/GT and CG/CG were minimum. AAG/CTT repeats motifs was the highest in tri-nucleotide followed by AGC/CTG and AGG/CCT, while CCG/CGG, ACG/CGT and ACT/AGT were lowest （ 〈 1%）. The repeat motifs were very few in tetra-nucleotide, petra-nucleotide and hexa-nucleotide and had no obvious differences. The SSR number of decreased with the increased number of repeats and length of repeats.