鯷科物種的DNA條碼之確立及其應用–仔魚鑑定及類源分析

DNA Barcode of Engraulid Species and Its Application –Larval Fish Identification and Phylogenetic Analysis

魏可婷(Ke-Ting Wei)

指導教授 ： 丘臺生

國立臺灣大學/生命科學院/動物學研究所/碩士(2012年)

https://doi.org/10.6342/NTU.2012.00099

摘要

鯷科魚種為我國魩鱙漁業主要漁獲。1976以來，因發展大目袖網而漁獲效率增加，需要有效的漁業管理。此漁業之系群組成及過漁與否為管理之關鍵資訊，亟待釐清。我希望在分子層級上，利用DNA之鹼基之特性估計系群之物種組成。已知鯷科在台灣有五屬十二種，其鑑定是以形態為依據，DNA分析可以強化目前之信度，並呼應學界擬建立物種生命條碼之主張。本研究使用mt COI序列作為標記，為11個鯷科魚種建立標準條碼，評估其在鑑定上可用程度，以及鑑定度與源系之親疏程度關係。
利用種間及種內差距比值可知，其最小比值為28.8，代表COI生命條碼有相當的種間辨識力，足夠用於進行鯷科魚種鑑定。此條碼之確立，亦發現了表型相似種，顯示此鑑定方法亦可彌補形態鑑定上的不足。利用近鄰連結法進行類源分析後發現，其支序圖支持形態所決定的演化關係，因此生命條碼之距離與演化時間長短一致。為了讓物種鑑定及漁業資源調查更便利，此研究也設計主要漁獲物種之專一性引子使用於多工聚合酶連鎖反應。此引子具有高度專一性，能夠提高鑑定效率並減少人為所造成的誤差。用此引子實測系群組成，並與形態調查相比，雖部分物種有5.7%差異，仍然能反應主要的物種組成。且將此組成數對關係經對數轉換後，卡方檢定顯示分子與形態調查資料有一致性。故以分子方式進行漁獲組成實測有其發展潛力。

關鍵字

鯷科 ； 生命條碼 ； 鑑定 ； 類源分析 ； 多工引子

並列摘要

Anchovy species are major components in Taiwanese larval fisheries. High efficient large-wing net was imported from Japan in 1976, and effective and reasonable management is highly expected onward. Catch species composition and stock status become highly concerned in the management plan. Currently 5 genera and 12 species were identified morphologically. This work attempts to use DNA analysis to fortify the reliability of species identification. In this study, I found mt COI is an effective marker specifically, and can be established as a standard barcode (s-barcode) sequence. The evaluation of sequence reliability indicated that the marker can reinforce the findings from morphological identification. The consensus tree topology between morphology and molecule examination exhibited that differences between species barcodes are unlikely random.
The ratios of inter-specific distance to that of intra-specific were 28.8 minimally. It represents COI barcode is feasible to identify anchovy species with fairly high confidence. Furthermore, the sequences also uncovered a cryptic species due to morphological convergence. To facilitate species identification and stock composition, a battery of species-specific primers for 8 major species were developed, and evaluated to be efficient in identification and also minimal in bias. Real catch samples were subjected to the designed primer sets to validate their application. The results were fairly in agreement with morphological findings with a maximal difference of 5.7%, and χ2-test based on logarithmic scale indicated that no significant difference found with molecular and morphological compositions. Therefore, s-barcodes and their application are promising in both theoretical and practical perspective.

並列關鍵字

Engraulid ； DNA barcode ； identification ； phylogenetic analysis ； multiplexer primer

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