以葉綠體及核微衛星DNA標記探究台灣水青岡之族群遺傳結構

Abstract

台灣水青岡(Fagus hayatae Palib.)是法定珍稀植物之一，在台灣目前主要分佈在台灣地區的插天山自然保留區、銅山地區、及幾處新發現的單獨山頭族群，此外於大陸四川、湖北、浙江等地也有零星分佈。本研究係對此具有滅絕危機的物種進行族群遺傳研究，檢測其族群間葉綠體DNA兩處片段trnL–F 與 rbcL–atpB之核苷酸變異度；以及挑選三組用於圓齒水青岡(Fagus crenata)之微衛星DNA引子對來應用於增幅台灣水青岡之微衛星DNA片段，對台灣九處分布族群以及大陸三處族群進行分析。研究結果顯示台灣水青岡葉綠體標記序列之變異度相當低，且於中國大陸之近緣分類群相似，但雪山山脈之族群（北插天山、羅培山、拉拉山、鳥嘴山、阿玉山）和中央山脈族群（蘭崁山、大白山、太平山山毛櫸步道－銅山）二者之間已有分化情形；微衛星分析之結果則顯示台灣各族群間分化度較低，大陸三處族群分化度較高，並以浙江族群最為顯著，但由貝氏族群遺傳結構分析則顯示，台灣族群與大陸三處族群，仍全部應屬於同一類分群。本研究之結果肯定微衛星序列之分析可提供較多的遺傳資訊，有助於釐清台灣水青岡之族群遺傳結構，未來可更加利用於保育生物學的工作上。

Fagus hayatae Palib., a rare and statutory-conserved plant in Taiwan, is distributed in Chatienshan Nature Reserve, Tongshan area, and few new single mountain areas. It can also be found in Sichun province, Hubei province, and Zhejiang province in China. A population genetics research on this endangered species was conducted by using chloroplast trnL–F and rbcL–atpB regions; three microsatellite markers developed for Fagus crenata were also examined in Fagus hayatae on the nine populations in Taiwan and three populations in China. Results showed that a low variation in Taiwan's populations using chloroplast markers, and a close relationship with the related taxa from China. Results also indicated a clear divergence of the populations from Syue Mountain (Beicha, Loupei, Lala, Niauzui, and Ayu) and Central Mountains (Lenkan, Dabai, Taipin Beech Trail, and Tongsan). By conducting microsatellite analysis, populations in Taiwan exhibited low level of genetic variation, while populations in China had higher level of genetic variation, especially for Zhejian’s population. Nevertheless, results of Bayesian clustering analysis suggested that populations in Taiwan and China should be considered as a single genetically distinct group. The results from microsatellite data provide more genetic information and therefore can be a great resource for further population genetics studies, hopefully provide applications to conservation biology of Fagus hayatae in Taiwan.