台灣地區溪狡蛛(蜘蛛目:跑蛛科)族群遺傳結構及親緣地理關係之探討
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Date
2010-12-??
Authors
羅英元
陳世煌
Ying-Yuan Luo, Shyh-Hwang Chen
Journal Title
Journal ISSN
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Publisher
國立臺灣師範大學生命科學學系
Department of Life Science, NTNU
Department of Life Science, NTNU
Abstract
台灣的中央山脈縱貫南北、地形高聳複雜，為台灣島內物種分布的天然地理屏障，一般認為節肢動物如昆蟲和蜘蛛等具有良好的擴散能力，族群間的交流不易被地形所阻隔。然而徘徊性的溪狡蛛(Dolomedes raptor) 生活棲所侷限於池塘或溪潤等有水的潮濕、環境，若蛛未見遷絲、空飄的行為，擴散能力不佳，其族群分化模式是否與結網性的蜘蛛不同，有待進一步探討。本研究利用粒線體cytochrome oxidase subunit I (CO 1) 基因部分序列探討溪狡蛛之族群遺傳結構，總共分析來自臺灣地區21 個採樣點、共153 隻個體。獲得CO I 基因部分序列長度617坤，包括34 個變異位點、23個基因型。由AMOVA 分析得知台灣地區溪狡蛛的遺傳結構在族群間有顯著的差異，且neighbor-joining 以及maximum parsimony 親緣關條樹型圖皆顯示台灣地區溪狡蛛可分為北部、中南部和東部三大系群。族群問遺傳分化指數則顯示台灣地區溪狡蛛族群間基因交流會受到山脈和水系的阻隔，具有「區域性分化」的現象，其分化模式和具有良好擴散能力的人面蜘蛛截然不同。而中部和南部族群間的基因交流則較為順暢，由於中部和南部是台灣最主要的農耕區，地勢平坦，推測溪狡蛛可利用人工開鑿的渠道，在各大水系間進出有關。溪狡蛛在台灣東部較為罕見，大多分布在中央山脈以西的山區，且和生活習性相似的褐腹狡蛛(Dolomedes mizhoanus) 少有共域棲息的現象，minimum spanning network 也顯示東部溪狡蛛族群是由北部擴散而來，且遺傳多樣性較低，推測溪狡蛛較不適應東部鴻急的溪流，其族群可能曾受到強烈瓶頸效應的影響;或可能是族群不易擴散到東部，東部族群受到創始者效應、強烈選汰的結果，仍需更進一步的調查研究。
Dolomedes raptor may have weak dispersal ability because of their habitats restricted in water environment, mostly along the grassy bank of ponds, rocks along the streams or creeks, without the ballooning behavior, and distributed at elevations below 1000 m. Moreover, the Central Mountain Range(CMR) and rivers in Taiwan form a natural geographic barrier for many organisms in the island. Therefore, we chose D. raptor to investigate their population genetics and phylogeography in Taiwan. We used the partial sequence of mitochondrial DNA cytochrome oxidase subunit I (CO 1) as a genetic marker in this study. A total of 153 individuals from 21 localities in Taiwan were obtained. The length of sequenced CO I gene was 6l7bp, including 34 polymorphism sites and 23 haplotypes. Analysis of AMOVA indicates that genetic structures are different significantly among populations. Phylogenetic trees generated from both Neighbor-joining and Maximum parsimony methods showed that D. raptor in Taiwan could be grouped into three major lineages, namely northern, eastern and central-southern lineages. All the FST values are high between populations, except for those between the central and southern, the central and central-northern populations (FST = 0.10299-0.26942). It indicates populations of D. raptor in Taiwan exhibited genetic differentiation is resulting from isolations by both the mountains and the lands between basins. The differentiation model of D. raptor is similar to those of primary freshwater fishes, but not Nephila pilipes， an orb-web spider, with strongly dispersal ability. Moreover, the gene flow between south and central populations was not isolatβd. It might be resulted from the southern and central parts of Taiwan that have a smooth topology, with complex drainage systems for agriculture and are frequently irrigated by the people.Minimum spanning network showed that the eastern population was derived from the northern population. However, the genetic diversity in east
Dolomedes raptor may have weak dispersal ability because of their habitats restricted in water environment, mostly along the grassy bank of ponds, rocks along the streams or creeks, without the ballooning behavior, and distributed at elevations below 1000 m. Moreover, the Central Mountain Range(CMR) and rivers in Taiwan form a natural geographic barrier for many organisms in the island. Therefore, we chose D. raptor to investigate their population genetics and phylogeography in Taiwan. We used the partial sequence of mitochondrial DNA cytochrome oxidase subunit I (CO 1) as a genetic marker in this study. A total of 153 individuals from 21 localities in Taiwan were obtained. The length of sequenced CO I gene was 6l7bp, including 34 polymorphism sites and 23 haplotypes. Analysis of AMOVA indicates that genetic structures are different significantly among populations. Phylogenetic trees generated from both Neighbor-joining and Maximum parsimony methods showed that D. raptor in Taiwan could be grouped into three major lineages, namely northern, eastern and central-southern lineages. All the FST values are high between populations, except for those between the central and southern, the central and central-northern populations (FST = 0.10299-0.26942). It indicates populations of D. raptor in Taiwan exhibited genetic differentiation is resulting from isolations by both the mountains and the lands between basins. The differentiation model of D. raptor is similar to those of primary freshwater fishes, but not Nephila pilipes， an orb-web spider, with strongly dispersal ability. Moreover, the gene flow between south and central populations was not isolatβd. It might be resulted from the southern and central parts of Taiwan that have a smooth topology, with complex drainage systems for agriculture and are frequently irrigated by the people.Minimum spanning network showed that the eastern population was derived from the northern population. However, the genetic diversity in east