蒙古冰草分子核型分析

Molecular Karyotype of Agropyron mongolicum Keng

利用荧光原位杂交技术,在蒙古冰草染色体组上进行5S rDNA、45S rDNA以及重复序列pAs1 DNA序列的定位,通过荧光原位杂交信号的强弱、数量、位置进行蒙古冰草染色体的配对及核型分析。结果表明:蒙古冰草染色体组总长度为91.788μm,平均绝对长度为13.113μm,最长染色体与最短染色体的长度比值为1.446,具有2对随体,分别位于第2号染色体和第4号染色体的短臂上,没有臂比大于2∶1的染色体,核型不对称系数为56.96%,核型类型属于1A型,核型公式为2n=2x=14=10m(2SAT)+4sm(2SAT)。5S rDNA序列和45S rDNA序列分别位于第2号和第4号染色体的短臂上,有5对染色体两端都检测到明显的pAs1 DNA荧光信号,有2对染色体只有一端检测到明显的pAs1 DNA荧光信号。荧光原位杂交技术大大提高了染色体核型分析的可靠性,为冰草属内植物的分类和育种提供了细胞学依据。

In this study,5S rDNA,45S rDNA and repetitive sequence pAs1 DNA on the chromosome of the Agropyron mongolicum Keng were located by fluorescence in situ hybridization(FISH)technology.Then the chromosome pairing and karyotype analysis of Agropyron mongolicum Keng were carried out by the intensity,quantity and location of FISH.Results showed that:(1)The total length of the chromosome group was 91.788μm,the average absolute length was 13.113μm,the length ratio of the longest chromosome to the shortest chromosome was 1.446,and it had two pairs of satellite,which were located on the short arms of chromosome 2 and 4 respectively.There was no chromosome with arm ratio greater than 2∶1,the coefficient of karyotype asymmetry was 56.96%,the karyotype belonged to 1A,and the karyotype formula was 2n=2x=14=10m(2SAT)+4sm(2SAT).(2)The 5S rDNA sequence and 45S rDNA sequence were located on the short arm of chromosome 2 and 4,respectively.The fluorescence signal of pAs1 DNA was detected at both ends of 5 pairs of chromosomes and only one end of 2 pairs of chromosomes.Fluorescence in situ hybridization technology greatly improved the reliability of karyotype analysis,and provided cytological basis for the classification and breeding of Agropyron Gaertn.