蓝猪耳45S rDNA荧光原位杂交作图及其核型分析

45S rDNA-FISH Mapping and Karyotype Analysis of Torenia fournieri L.

以番茄45S rDNA为探针，结合核型分析和荧光原位杂交（FISH）技术，对蓝猪耳染色体的核型以及45S rDNA在染色体上的定位进行了研究。结果表明，蓝猪耳染色体的核型为1A型，核型不对称系数为57．46，染色体相对长度变异范围为4．455％～6．990％，最长染色体与最短染色体的比值为1．57，染色体相对长度组成为2L＋4M2＋12M1，核型公式为2n=2x=18=14m＋4sm（2SAT）。在蓝猪耳体细胞有丝分裂中期染色体和间期核中，均发现45S rDNA有2个杂交信号，且信号在有丝分裂中期位于第5对染色体短臂近着丝粒处。基于上述结果绘制了蓝猪耳染色体的核型图。

Karyotype analysis and 45S rDNA-florescence in situ hybridization （FISH） mapping of Torenia fournieri L. were performed by using Lycopersicon esculentum 45S rDNA as a probe. The T. fournieri karyotype was classified into the type IA in the Stebbins＇ category. The asymmetry index was 57.46. Variation in chromosome relative length ranged from 4. 455% to 6. 990%. The ratio of the longest over the shortest length of chromosomes （L/S） was 1.57. Chromosome constitution of relative length was 2L ＋4M2 ＋ 12M1. The kar／ yotype formula can be represented as 2n =2x = 18 = 14m ＋4sm （2SAT）. Two hybridized signals were found on the fifth pair of chromosome near the centromere at the metaphase and in the interphase nucleus of T. fournieri. An idiogram was obtained based on these findings.