黔蚋唾腺多线染色体研究

Observation on Salivary Gland Polytene Chromosomes of Simulium qianense (Diptera:Simuliidae)

选取黔蚋的成熟幼虫,用改良苯酚品红染色法进行唾腺多线染色体制备,并进行测量、描述及分析。结果表明,黔蚋多线染色体数目为3对(2n=6)。按其长度降序排列,分别编号为Ⅰ、Ⅱ和Ⅲ号。Ⅰ号染色体具中央着丝粒,Ⅱ和Ⅲ号染色体均为亚中央着丝粒,着丝粒区浅染膨大,易于识别。核仁组织区、巴氏环和双泡均位于Ⅱ号染色体短臂。某些个体存在倒位现象,倒位率为33%(32/97)。结果显示黔蚋多线染色体的着丝粒、核仁组织区、巴氏环、双泡、宽深带及浅染膨大区等主要特征性结构的位置及形态恒定一致,可作为该种的重要鉴别特征。

The salivary gland polytene chromosomes of Simulium qionense was observed with wild larvae collected from Guiyang, Guizhou Province. Using an upgraded method of preparation, the polytene chromosomes of the larval salivary glands of S. qianense were observed and analysed. The results showed three pairs of chromosomes （2n=6） arranged from the longest to the shortest. Chromosome I was metacentric while chromosomes Ⅱ and Ⅲ were submetacentrie. The eentromeric regions distinctly expanded and were easily recognized. The nucleolar organizer situated near the eentromeric band of the short arm of chromosome Ⅱ. The Balbiani ring and double bubble all located near the tip of the short arm of chromosome Ⅱ. There were inversions in Some individuals, with an inversion frequency of 33% （32/97）. The study revealed constant localization and morphology of the principal landmarks （namey, centromere, nucleolar organizer, Balbiani ring, double bulge, band and puff） which can be considered as distinguishable features of S. qianense.