中文摘要：

【目的】利用基因组荧光原位杂交（genomic in situ hybridization,GISH）技术,对黄瓜（Cucumis sativus L.,2n=2x=14）种内两个变种（栽培黄瓜C.sativus var.sativus和野生黄瓜C.sativus var hardwickii）进行中期染色体分析,建立黄瓜变种染色体核型的快速分析方法,为黄瓜细胞分子遗传学研究提供基础。【方法】以栽培黄瓜‘9930’和野生黄瓜C.sativus var.hardwickii为材料,利用CTAB法提取栽培黄瓜‘9930’的基因组总DNA,采用缺刻平移法,将栽培黄瓜‘9930’基因组DNA和45S r DNA分别利用地高辛和生物素标记为探针,与栽培黄瓜‘9930’和野生变种C.sativus var.hardwickii的中期染色体进行荧光原位杂交,根据杂交结果显示的栽培黄瓜与野生变种每条染色体GISH荧光带型的不同,结合45S r DNA位点信号特征,区分栽培黄瓜与野生变种的每条染色体,并进行核型分析。【结果】荧光原位杂交结果显示,GISH信号并非平均分布于所有染色体上,而是在不同染色体的特定部位产生独特的信号,且两个变种间中期染色体的GISH信号模式差异显著。在栽培黄瓜‘9930’有丝分裂中期染色体上,除了6号染色体仅在短臂末端和近着丝粒处产生GISH信号外,其他染色体上的GISH信号集中分布于染色体的两端和近着丝粒的一侧或两侧,且每条染色体的信号特征差异明显;45S r DNA信号主要分布于‘9930’的第1、2、3、4和7号染色体的近着丝粒处,有3对强信号和2对弱信号。在野生黄瓜C.sativus var.hardwickii有丝分裂中期染色体上,杂交信号的位置及强弱与栽培黄瓜‘9930’表现明显不同,近着丝粒处均有GISH信号,但仅在第1、2、4和5号染色体的一端产生GISH信号,45S r DNA信号仅出现在第1、2和3号染色体上,表现为第1号染色体上信号极强,第2和3号染色体上信号极微弱。这些结果显示,以栽培黄瓜基因组DNA为探针的荧光原位杂交能反应出两个变种中?

英文摘要：

[Objective] Using genomic in situ hybridization （GISH）, metaphase chromosome analysis was performed for two variants of cucumber （C. sativus L., 2n = 2x = 14） [cultivated cucumber （C. sativus var. sativus） and wild cucumber （C. sativus var.hardwickii）] to quickly establish the chromosome karyotype of cucumber varieties, which will provide useful information for molecular cytogenetic research of cucumber. [Method] Genomic DNA from cultivated cucumber ＇9930＇ isolated using CTAB method and 45S rDNA were labeled with Dig-dUTP or Bio-dUTP through nick-translation method, and used as probes and hybridized onto the metaphase chromosomes of cultivated cucumber itself and wild cucumber using genomic in situ hybridization technique. Individual chromosome of two cucumber variants was analyzed based on the GISH banding, and 45 rDNA signals as well, and the karyotypes of these two variants were constructed. [ Result] The GISH results showed that cucumber genomic DNA probes exhibited distinguished signal patterns on the chromosomes of two variants. The unique distribution and intensity of signals were observed on each chromosome, rather than the even distribution of signals across all chromosomes. For C. sativus var. sativus ＇9930＇, GISH produced obvious signals at the both ends of chromosomes and pericentromeric heterochromatin regions on all other chromosomes except for chromosome 6 which only gave signals at the end of short arm and pericentromeric heterochromatin region. The signal patterns from each chromosome exhibited an obvious difference. 45S rDNA loci were mapped adjacent to centromeric regions on chromosomes 1, 2, 3, 4 and 7, among which three pairs of strong signals and two pair of weak signals were observed. However, the signal patterns from wild cucumber showed an obvious difference compared with that from ＇9930＇. The GISH signals were observed only at one end of chromosomes 1, 2, 4 and 5, and pericentromeric heterochromatin regions of all chromosomes. 45S rDNA signals were observed on