利用454高通量测序技术对核桃( Juglans regia)基因组进行了部分测序,并利用测得的序列进行核桃基因组微卫星特征分析。结果表明:研究共测得了104.5 Mb的核桃基因组序列,经序列组装得到了9787个微卫星重复序列。其中六碱基重复类型的重复数目最多,共5883个,占重复序列总数的60.11%;其次是单碱基重复类型(1289个)和四碱基重复类型(889个),分别占重复序列总数的13.17%和9.07%;另外二碱基重复768个,三碱基重复549个,五碱基409个,分别占重复序列总数的7.85%、5.61%和4.18%。在单碱基重复类型中,重复单元最多的为A/T;二碱基重复中,AT/TA和AG/CT为主要优势重复类型;三碱基、四碱基和六碱基重复类型中,AAN、AAAN和AAAAAN是主要的优势重复类型;五碱基重复类型中,AGATG和AAAAT 是主要的优势重复类型。在核桃微卫星序列中,A/T碱基含量丰富,而C/G碱基含量相对较少。试验还对核桃基因组微卫星的长度及各碱基重复类型的长度分化进行了研究,结果发现核桃基因组微卫星以第二类(长度<20 bp)为主,且长碱基重复类型较短碱基重复类型长度分化程度低,稳定性高。
We sequenced the partially genome of Juglans regia with a 454-high-throughput sequencer and analyzed the character-istics of microsatellites based on the obtained sequences.Totally, we sequenced 104.5 Mb genome sequences of J.regia and detected 9 787 microsatellites (SSRs) in the assembled genome sequence.Among these SSRs, the hexanucleotied re-peats are the most abundant (5 883), accounting for 60.11%of the repetition sequence.Monomers (1 289) and Tetranu-cleotide (889) are the second and third abundant.There are 768 dinucleotide, 549 trinucleotide and 409 pentanucleotide, accounted for 7.85%, 5.61%and 4.18% of repetitive sequences, respectively.For the composition of microsatellites, A/T repeats are the most frequent motifs in mononucleotide repeats, and AT/TA, AG/TC repeats are the richest in dinu-cleotide repeats, while AAN, AAAN and AAAAAN repeats are dominant in tri-, tetra-and hexanucleotide repeats.For pentanucleotide, AGATG and AAAAT are the main repeats.In the microsatellite sequence repeats of Juglans, nucleotide A/T has a large content, while the C/G content is relatively small.In Juglans genome, the second type of SSRs (length〈20bp ) is predominant .