利用排遺DNA標定法探討金門地區水獺之族群遺傳結構與雌雄播遷模式之差異

Abstract

本研究於2003年四月、八月與2004年二月，在金門與烈嶼共15個水域採集新鮮水獺排遺，萃取374份排遺樣本中的水獺DNA，並利用15個具有多型性的水獺微衛星體基因座對排遺進行個體標定與性別鑑定；共標定出63隻水獺個體，包括37隻雄性與26隻雌性。遺傳資訊分析顯示金門存在著小尺度的族群遺傳結構，分為西北、西南、東北、東南4群。而由追蹤個體移動的結果顯示，在群間移動的個體其移動方向皆指向島中央水域，推測4個次族群藉由島中央的水域達到有限的遺傳交流。其中雌性個體的遺傳分化趨勢較雄性個體顯著，且在不同分區間移動的6隻個體中有5隻為雄性，推論金門的水獺族群呈現雄性偏差的播遷(male-biased dispersal)趨勢。本研究以排遺DNA為材料，配合遺傳資訊與追蹤個體移動方向，探討了小地理尺度下的水獺族群遺傳結構與性別偏差的播遷模式。

We use noninvasive molecular methods to investigate the fine scale population structure and to trace the movement pattern of Eurasian otter (Lutra Lutra) in Kinmen. We collected 513 fresh spraints of otters from 15 sites in April and August 2003, and February 2004. DNA was extracted from these spraints and genotyped by 15 microsatellite markers and SRY gene. Sixty-three individuals, including 36 males and 27 females were identified based on the results of genotyping. These otters could be divided into 4 subpopulations on a fine scale basis. We used a genetic distance matrix to analyze the degree of genetic differentiation between these subpopulations and found that female otters show a higher differential tendency. Furthermore, we found only 6 of 63 individuals moved between different subpopulation. Of which, five were males. Therefore, we concluded that the otter population in Kinmen shows sex-biased dispersal pattern.