以微隨體DNA研究粗首（Zacco pachycephalus）的保育遺傳

Conservation Genetics of Zacco pachycephalus by Microsatellite DNA Locus Analyses

粗首鱲是廣泛分布於台灣北部及西半部河川的特有種魚類，東部花東地區原本並沒有分布，現在花東地區溪流內的粗首鱲是人為放流的結果。我們利用8個微隨體基因座（microsatellite loci），對來自全省不同溪流的粗首鱲族群進行歸類分析（assignment analysis），可以獲得97%的正確率，顯示不同溪流的粗首鱲間已有一定的分化，並可以微隨體基因座作為分子標記，正確判別出粗首鱲個體的來源溪流。同樣對淡水河三大支流進行歸類，只有81%的正確率，顯示同一溪流中的次族群間遺傳分化不高，或者存在著頻繁的基因交流。以歸類分析追蹤東部的粗首鱲個體來源，發現東部的粗首鱲族群源自北部及中部溪流的多次放流。由粗首鱲的研究結果可知，利用微隨體基因座加上歸類分析方法，可有效地分析出淡水魚個體的可能來源，對保育工作尤其是淡水魚類保育及放流的管理而言，是很有用的工具。 Zacco pachycephalus (Günther) is a common minnow endemic to freshwater streams in thenorthern and western Taiwan, and has been recently introduced to streams in the eastern Taiwan. Weapplied eight microsatellite DNA loci to make an assignment test to determine the genetic relationships of its populations among the streams with the success rate of 97%. This suggested that there wassignificant differentiation in the populations among the streams. When the assignment test was applied toindividual fish from three tributaries of the Tamshui River, the success rate was 81%, indicating a lowgenetic differentiation among the populations in the same river. When the test was applied to theindividual fish from the streams of the eastern Taiwan, it was able to identify their source populations inthe northern and western Taiwan. Accordingly, the microsatellite DNA locus analysis is an effectivemethod for determining genetic differentiation of stream fish and also for identifying source populationsof introduced populations. The analysis is useful for conservation and management of freshwater fishes.