兴义维蚋多线染色体研究(英文)

Polytene chromosomes of Simulium (Wilhelmia) xingyiense (Diptera:Simuliidae) from China

首次在国内对兴义维蚋Simulium (Wilhelmia) xingyiense的多线染色体进行研究,并提供其多线染色体标准图。选取兴义维蚋的成熟幼虫,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:兴义维蚋多线染色体数目为3对(2n=6)。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染色体。核仁组织者区位于Ⅰ号染色体短臂近着丝粒端。巴尔比尼氏环和双泡位于Ⅱ号染色体短臂近中央位置。3对染色体的着丝粒区可形成明显的染色中心。兴义维蚋多线染色体具有多态性的倒位,倒位频率为0.64。兴义维蚋多线染色体的着丝粒、核仁组织区、巴氏环、双泡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。其多态性的倒位可为该蚋种在细胞水平上进行蚋类分类鉴别和系统发育等研究提供基础资料。

A standard photographic map of Simulium （Wilhelmia） xingyiense Chen and Zhang was constructed from larval salivary gland polytene chromosomes and is described herein. Polytene chromosomes from wild larvae collected from three populations in Guiyang, Guizhou Province, China were analyzed. By using an upgraded method of preparation, the polytene chromosomes of the larval salivary glands of S. （ W. ） xingyiense were observed and analysed. The results indicated that this species has three pairs of chromosomes （2n = 6 ） which are arranged from the longest to the shortest. Chromosome I is metacentric while the chromosome 11 and III are submetacentric. The nucleolar organizer is situated near the centromeric band of the short arm of chromosome I ~ The Balbiani ring and double bubble are located about the middle of short arm of chromosome I1. The pericentric heterochromatin of all chromosome arms forms an evident chromocenter. High inversion polymorphism is observed, with 0.64 inversions per individual. Thus, the polytene chromosomes of S. （ W. ） xingyiense are species-specific. Inversion is one of the characteristics of polytene chromosomes of S. （W.） xingyiense.