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題 名 | 缺乏遺傳變異亟待保育的津田氏大頭竹節蟲(竹節蟲目:竹節蟲科)=Lack of Genetic Variation Shows the Urgency of Conservation for Megacrania tsudai Shiraki (Phasmatodea: Phasmatidae) |
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作 者 | 吳怡欣; 陳攸雁; 楊平世; 葉文斌; | 書刊名 | 臺灣昆蟲 |
卷 期 | 32:1 2012.03[民101.03] |
頁 次 | 頁97-105 |
分類號 | 387.749 |
關鍵詞 | 津田氏大頭竹節蟲; 16S核醣體去氧核醣核酸; 保育昆蟲; Megacrania tsudai Shiraki; 16S rDNA; Threatened insect; |
語 文 | 中文(Chinese) |
中文摘要 | 分布於恆春半島及綠島少數地點的津田氏大頭竹節蟲(Megacrania tsudai Shiraki),數量稀少,被列為珍貴稀有保育類動物。此物種的研究多關於形態與生活史的描述,未有遺傳組成相關資料。本研究利用粒線體16S rDNA序列,探討屏東港口、九棚及台東綠島三地區津田氏大頭竹節蟲族群間的遺傳多樣性及地理親緣關係。基於保育原則,各樣本僅採成蟲中足一小段跗節或卵進行研究,而將個體釋回。除九棚及綠島的卵樣本外,所有的跗節樣本均可複製出DNA,總計從46隻個體的樣本中成功複製增幅其中的23個樣本。16S rDNA區段約550個鹼基的結果顯示,各地津田氏大頭竹節蟲族群間全無遺傳變異,基因已完全均質化。推論台灣目前的津田氏大頭竹節蟲族群都是源自某一小族群或少數個體,顯現出拓荒者效應(founder effect)或曾經歷過瓶頸效應(bottleneck effect)的可能性。此遺傳組成非常不利於此物種的存活及保育,急需投入更多的保育措施。除列為保育物種外,更需突破分佈地域的侷限性,增加其棲地範圍,也需增加研究樣本,以保留或復育可能存在的遺傳變異個體及其後代。 |
英文摘要 | The distribution of Megacrania tsudai Shiraki, a threatened stick insect species in Taiwan, is limited to the Hengchun Peninsula and Green Island, with only a small population in each locality. Previous studies on this insect were mostly focused on its morphology and life history. In the present study, the 16S rDNA gene was used as a marker to study the genetic diversity, phylogenetic relationships, and phylogeography of M. tsudai. Crude DNA was extracted from 46 samples of eggs or partial mid-leg tarsi collected from three populations (Jioupeng, Kankau and Green Island). Sequence analyses of 16S rDNA, ~550bp, from 23 successfully amplified samples showed no variation at all between and within populations. This result suggests that the populations of M. tsudai in Taiwan may have either descended from a limited number of ancestors (founder effect), or have experienced a bottleneck effect due to a small population size and restricted habitats. From a conservation point of view, the perfect genetic homogeneity of the M. tsudai populations will have a negative impact on the long-term survival of this species in Taiwan. In addition to enhancing their legal protection, it would also be helpful to conserve this species by preserving its habitats and broaden its distribution range. It is also very important that we explore potential genetic variation and preserve it in the wild populations. |
本系統中英文摘要資訊取自各篇刊載內容。