Metaphase Karyotypes of Fruit Flies of Thailand (III): Six Members of the Bactrocera Dorsalis Complex

泰國之果實蠅核型(III)：東方果實蠅群之六個種類

Visut Baimai ； Jaros Phinchongsakuldit ； Wachareeporn Trinachartvanit

《Zoological Studies》 38卷1期 (1999/01) Pp. 110-118

摘要

檢查從被感染為害的果樹採集到的六種屬於東方果實蠅群的果實蠅：Bactrocera propinqua, B. irvingiae,B carambolae, B. pyrifoliae, B. arecae,以及B. melastomatos的核型發現，染色體上異染色質的比例和分布截然不同。最常見的型式為B. irvingiae和B. propinqua，和東方果實蠅(D. dorsalis)的型式很相似，同樣被歸為第一類核型。B. carambolae和B. pyrifoliae的X染色體和體染色體著絲點附近的異染色質型式很相似，可歸為第四類核型。B. carambolae的體染色體和X染色體的異染色質型式不同於具他種類。B. melastomatos的X和V染色體都很小，無法歸入任何一類早先畫分的核型中。這些發現顯示異染質分化在泰國的果實蠅種類的核型進化是很重要的。這種不同的異染質型式可作為鑑定這些東方果實蠅群近緣種的依據。

關鍵字

東方果實蠅群 ； 有絲分裂染色體 ； 異染色體 ； 核型進化

並列摘要

Six species of fruit flies belonging to the Bactrocera dorsalis complex used in this study include B. propinqua, B. irvingiae, B. carambolae, B. pyrifoliae, B. arecae, and B. melastomatos. Wild samples collected from infested fruits of various host plants were examined cytologically. Analysis of mitotic karyotypes of these species has revealed distinct patterns of metaphase chromosomes due to different amounts and distribution of constitutive heterochromatin in sex chromosomes and autosomes. The general pattern of mitotic karyotypes of B. irvingiae and B. propinqua resembles that of B. dorsalis, and they are classified in Group 1. Likewise, B. carambolae and B. pyrifoliae exhibit mitotic karyotypes of Group 4 showing specific patterns of heterochromatin in the centromeric regions of the X chromosome and autosomes. Bactrocera arecae exhibits distinctive patterns of pericentric heterochromatin in autosomes and sex chromosomes. Interestingly, metaphase chromosomes of B. melastomatos do not match with any groups of mitotic karyotype categorized earlier because of the very small size of the X and Y chromosomes. These findings suggest the significance of heterochromatin differentiation in karyotypic evolution of these species of fruit flies in Thailand. Such distinctive patterns of heterochromatin in mitotic karyotype are useful as diagnostic characters for separation of these closely related species of the B. dorsalis complex.

並列關鍵字

Bactrocera dorsalis complex ； Mitotic chromosomes ； Heterochromatin ； Karyotypic evolution