枸杞基因组微卫星特征分析

Characteristic Analysis of Microsatellites of Lycium barbarum

利用Illumina HiSeq2500高通量测序技术对枸杞大麻叶品种进行简化基因组测序,对得到的序列利用生物信息学手段进行拼接后查找SSR。结果表明：共获得14 733个重复单元长度为2~6碱基的微卫星重复序列。其中3碱基重复的微卫星单元最为丰富,共9 799个,占66.5%;其次是2碱基重复类型（4 042个）和4碱基重复类型（519个）,分别占重复序列总数的27.4%和3.5%;另外5碱基重复281个,6碱基重复92个,分别占重复序列总数的1.9%和0.6%。通过分析发现3碱基重复类型丰度最高,优势序列为GTT/CAA、ACA、ATC;而6碱基重复丰度最低,其优势序列为TGTGTA、CATATA、AGCACC;在枸杞基因组微卫星序列中,A和T碱基含量相对较丰富。分析还发现,当枸杞基因组重复次数增加时,微卫星的丰度呈现出下降的趋势,随着基序长度的增加,下降的趋势越快,这意味着枸杞基因组中重复单元较短的微卫星变异速率比重复单元较长的微卫星变异速率快。

Restriction site associated with DNA sequencing （RAD-seq） was conducted on Lycium barbarum L. ＇da ma ye＇ by using Illumina HiSeq2500 sequencer. The gene sequence was then assembled,and SSR was detected by bioinformatics method. Totally,there were 14 733 microsatellites （SSRs） ranged from 2 to 6 bp. Amang them,trinucleotide repeats were the most abundant （9 799）,accounted for 66.5% of the to- tal,followed by dinueleotide （4 042） and tetranucleotide （519） repeats that accounted for 17.4% and 3.5% of the total, respectively. The numbers of pentanucleotide and hexanucleotide were 281 and 92, accounted for 1.9 % and 0.6 % of the total, respectively. Through the analysis,it was found that trinucleotide repeats were the most abundant,in which GTT/CAA,ACA and ATC were the most frequent motifs. Hexanucle- otide had the minimum proportion,in which TGTGTA, CATATA, and AGCACC were the most frequent motifs. In Lycium genome, A and T were the relatively richer nucleotides. It was also shown that, the abun2 dance of mierosattlites decreased with the increase of the number of repeats, and the length of different types of the sequences reduced differently, indicating that the mutation rate of short repeats was faster than long repeats.