台灣石蠙的族群遺傳結構

Population Structure Of Acrossocheilus paradoxus G命nther(Cyprinidae)

台灣石蠙分佈於台灣西部主要河川，為台灣特有的初級性淡水魚類，由於受到水系及山系的隔離，基因交流受阻，故其族群可能會有區域性分化的現象。由最近保育生物學的研究顯示，很多野生動物族群由於棲地喪失或分裂而面臨滅絕，所以必須發展合理的保育策略，而正確評估族群遺傳結構是有效經營管理的基礎。本研究乃根據RAPD指紋法，利用10個引子，偵測台灣石蠙在10個河系的族群遺傳變異，數據分析顯示族群間地理距離和遺傳距離呈正相關，並符合Isolation by distance的假說，不論是族群內或族群間均維持著基因的歧異度，在各河系內具有特定的遺傳標記，以分歧分類學原理重建台灣石蠙族群間的親緣關係，結果顯示台灣石蠙已有分化分群的現象，雖然台灣石蠙目前沒有滅絕之虞，但保護健全的自然族群則為保育工作之要務。 Acrossocheilus paradoxus is a primary freshwater fish endemic To streame of western Tainan. Genetic structure of A. paradoxus was examined by the random amplified polymorphic DNA (RAPD) fingerprinting method . Ten random 10-mer primers were screened for RAPD markers , and gave clear and consistent amplified products , which were used to assay the individuals collected from 10 streame . The RAPD data showed a positive correlation between genetic distances and geographical distances , supporting the model of isolation by distance. Genetic differentiation was mostly ascribed to low gene flow caused by geographical isolation. Comparison of the RAPD bands and the reconstructed phylogeny indicated that high genetic diversity existed within and between the populations of A. paradoxus.