臺灣的新歸化物種
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Date
1997-06-??
Authors
陳燕珍
陳進霖
黃生
Journal Title
Journal ISSN
Volume Title
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
裂葉月見草是新近歸化的外來物種。最初僅在臺灣東、西部海岸的宜蘭和桃園地區各發現一個族群，到了1996年，由於他們的快速擴張，已在山區和海岸邊蔓延開來。本報告即在探索如此快速散佈的植物其遺傳變異的分佈情形，在分析了五個族群的同功�t遺傳變異後，發現裂葉月見草的遺傳變異度偏低，能判讀的多型性基因座只有3個(P=12.0%)，平均異合度(HE)為0.062，族群分化指數(FST)是0.102，近交係數(FIS)高達-0.952。這結果顯示在臺灣的裂葉月見草偏好異配生殖，族群間有中度的分化但遺傳距離甚低(D<0.05)。對於這種新侵入的草本植物而言，分別在東西兩個族群所顯現的先驅者效應和單在桃園地區所發現的連鎖不平衡現象，可能是造成其族群分化的主要原因。
Oenothera laciniata Hill, one of the rapid expanded exotic weed, was found of restricted distribution initially in northern Taiwan. It had been reported in the sandy coast of Taoyuan and I-Lan counties, but has since been invading rapidly along the coastaline highway and the mountain traits. Patterns of genetic variation were studied at 15 isozyme loci in five sampled populations. Realitively low percentage of polymorphic loci (12.0%) and mean heterozygosity (0.062) indicated little of genetic variability across loci in overall populations. Based on inbreeding estimation, O. lacianata was found nearly complete outcrossing. Moderate population differentiation (FST=0.102) was existed among populations for three polymorphic loci. Results of genetic diversity analysis indicated that nearly 91% of total variation was distributed within populations (GST=0.09). This suggests a lack of barriers to gene flow among populations. The parameter of genetic distance (D) showed population divergence was low between populations (D<0.05) and to be identity in eastern Taiwanese populations (D=0.00). Moreover, linkage disequilibrium was found merely present in the Taoyuan population. However, since O. laciniata is a newly naturalized species, the founder's effect as well as the isolation between eastern and western local populations, may play roles on the differentiation between populations.
Oenothera laciniata Hill, one of the rapid expanded exotic weed, was found of restricted distribution initially in northern Taiwan. It had been reported in the sandy coast of Taoyuan and I-Lan counties, but has since been invading rapidly along the coastaline highway and the mountain traits. Patterns of genetic variation were studied at 15 isozyme loci in five sampled populations. Realitively low percentage of polymorphic loci (12.0%) and mean heterozygosity (0.062) indicated little of genetic variability across loci in overall populations. Based on inbreeding estimation, O. lacianata was found nearly complete outcrossing. Moderate population differentiation (FST=0.102) was existed among populations for three polymorphic loci. Results of genetic diversity analysis indicated that nearly 91% of total variation was distributed within populations (GST=0.09). This suggests a lack of barriers to gene flow among populations. The parameter of genetic distance (D) showed population divergence was low between populations (D<0.05) and to be identity in eastern Taiwanese populations (D=0.00). Moreover, linkage disequilibrium was found merely present in the Taoyuan population. However, since O. laciniata is a newly naturalized species, the founder's effect as well as the isolation between eastern and western local populations, may play roles on the differentiation between populations.