| 淡黄蚊蝎蛉染色体特征及其系统发育意义 |
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| 引用本文： | 苗颖,花保祯. 淡黄蚊蝎蛉染色体特征及其系统发育意义[J]. 昆虫学报, 2019, 62(6): 734-742. DOI: 10.16380/j.kcxb.2019.06.009 |
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| 作者姓名： | 苗颖 花保祯 |
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| 作者单位： | (西北农林科技大学植物保护学院, 植保资源与病虫害治理教育部重点实验室, 陕西杨凌 712100) |
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| 摘 要： | 【目的】染色体特征在昆虫系统发育研究中起着重要作用。然而，长翅目(Mecoptera)蚊蝎蛉科(Bittacidae)昆虫的染色体研究却比较匮乏。【方法】通过室内饲养获得淡黄蚊蝎Bittacus flavidus Huang & Hua各龄幼虫、蛹和成虫。取淡黄蚊蝎雄性末龄(4龄)幼虫、蛹和新羽化成虫精巢细胞进行染色体制片，通过4′,6-二脒基-2-苯基吲哚(4′,6-diamidino-2-phenylindole， DAPI)荧光染色，研究染色体核型、减数分裂行为和性别决定机制。【结果】结果表明，淡黄蚊蝎蛉的染色体数目为2n=26+X0，染色体均具有中着丝粒，核型高度对称。二价体绝对长度为(3.20±0.07)~(1.53±0.19) μm，相对长度为(5.31±0.29)~(2.73±0.24)，均呈梯度变化。淡黄蚊蝎蛉的减数分裂为交叉型，其中核的平均交叉频率为11.5，二价体的平均交叉频率为0.88。性别决定机制为XX/X0型。DAPI荧光带型显示，粗线期二价体一端呈现高亮的AT富集区块。【结论】染色体特征(包括染色体数目、染色体臂基本数和核型公式等)在蚊蝎蛉科中表现出显著变异，表明染色体重排(尤其是融合、断裂和倒位)在蚊蝎蛉科昆虫的谱系分化和染色体演化中起着重要作用。
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| 关 键 词： | 蚊蝎蛉科 细胞遗传学 核型 性别决定机制 减数分裂 系统发育 |
Chromosomal characteristics of the hangingfly Bittacus flavidus Huang & Hua (Mecoptera: Bittacidae) and their phylogenetic implications |
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| MIAO Ying,HUA Bao-Zhen. Chromosomal characteristics of the hangingfly Bittacus flavidus Huang & Hua (Mecoptera: Bittacidae) and their phylogenetic implications[J]. Acta Entomologica Sinica, 2019, 62(6): 734-742. DOI: 10.16380/j.kcxb.2019.06.009 |
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| Authors: | MIAO Ying HUA Bao-Zhen |
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| Affiliation: | (Key Laboratory of Plant Protection Resources and Pest Management, Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China) |
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| Abstract: | 【Aim】 Chromosomal characteristics play significant roles in phylogenetic analyses of insects. However, chromosomes in Bittacidae (Mecoptera) have rarely been studied to date. 【Methods】 Larvae, pupae and adults of the hangingfly Bittacus flavidus Huang & Hua were obtained by rearing in the laboratory. Chromosome preparations for the testes of the last (4th) instar larvae, pupae and newly-emerged adults of the hangingfly were stained with 4′,6-diamidino-2-phenylindole (DAPI) to investigate the karyotype, meiotic behavior, and sex determination. 【Results】 The results showed that the chromosome number of B. flavidus is 2n=26+X0, and all the chromosomes are metacentric, showing a symmetric karyotype. The absolute length of bivalents ranged from 3.20±0.07 to 1.53±0.19 μm, and the relative length from 5.31±0.29 to 2.73±0.24, with their size decreasing gradually from pair to pair. The meiosis of B. flavidus is chiasmate with a mean chiasma frequency of 11.5 per nucleus and a mean chiasma frequency of 0.88 per autosomal bivalent. The sex determination mechanism is of the XX/X0 type. Fluorescent bands with DAPI staining revealed a large AT-rich block covering one terminal region on all pachytene bivalents. 【Conclusion】 The chromosomes exhibit marked variations with respect to the diploid number, fundamental number and karyotype formula, suggesting that chromosome rearrangements (especially fusion, fission and inversion) play an important part in the lineage differentiation and chromosome evolution in Bittacidae. |
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| Keywords: | Bittacidae cytogenetics karyotype sex determination mechanism meiosis phylogeny |
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