台灣西部溪流構樹之遺傳結構與水系棲地關係

Relationship between Population Genetic Structure and Riparian Habitats of Broussonetia papyrifera Vent. on the Western Taiwan

何坤益(Kuenu-Yih Ho) ； 張景富(Jin-Fu Chang)

《國立臺灣大學生物資源暨農學院實驗林研究報告》 20卷3期 (2006/09) Pp. 165-174

https://doi.org/10.6542/EFNTU.200609_20(3).0002

摘要

Broussonetia papyrifera Vent. of Moracea, is a native riparian and dominant tree species at the altitude from 0 to 2000m in Taiwan. Since gene flow is suspected to be restricted mainly within a single river system, we hypothesize that plants of each river system might have rather distinct genetic structure due to limited gene flow. In the present study, 180 individual samples from 18 sampling sites (populations) in five river systems were studied using ISSR markers. The variation of 93 polymorphic ISSR bands, 78 bands were polymorphic in the samples were recorded. Analysis of the population genetic variances demonstrated that there were unremarkable Nei's genetic diversity, and conspicuous population differentiation between different river systems (H=0.1624, Gst=0.2476), with high level of gene flow (Nm=1.5192). The results were probably due to that the influence from the different environments did not restrict the gene flow but promote a lower genetic differentiation. The analysis of molecular variance (AMOVA) revealed that the components of variance among river systems was 24.21% (p＜0.001). Among populations within river systems was 13.01% (p＜0.001). Main variance within populations, shown to be significant, was 62.78% (p＜0.001). The results indicated that there is a considerable genetic diversification among river systems, and most of the diversification was between populations. Based on our mantel test, correlation coefficients among genetic variation among for 18 natural populations were significant, influenced by the geographical distribution but uninfluenced by the elevation. The cluster analysis and principal coordinate analysis revealed two major general groupings of northern and central-southern groups. The Gao-ping-shi river system was found to be a relatively isolated group by the cluster analysis. Cluster analysis and principal coordinate analysis (PCOA) also revealed that the genetic differentiation may be caused by different environments.

關鍵字

構樹 ； 簡單重複序列 ； 遺傳分化 ； 基因流 ； 遺傳變異

並列摘要

Broussonetia papyrifera Vent. of Moracea, is a native riparian and dominant tree species at the altitude from 0 to 2000m in Taiwan. Since gene flow is suspected to be restricted mainly within a single river system, we hypothesize that plants of each river system might have rather distinct genetic structure due to limited gene flow. In the present study, 180 individual samples from 18 sampling sites (populations) in five river systems were studied using ISSR markers. The variation of 93 polymorphic ISSR bands, 78 bands were polymorphic in the samples were recorded. Analysis of the population genetic variances demonstrated that there were unremarkable Nei's genetic diversity, and conspicuous population differentiation between different river systems (H=0.1624, Gst=0.2476), with high level of gene flow (Nm=1.5192). The results were probably due to that the influence from the different environments did not restrict the gene flow but promote a lower genetic differentiation. The analysis of molecular variance (AMOVA) revealed that the components of variance among river systems was 24.21% (p＜0.001). Among populations within river systems was 13.01% (p＜0.001). Main variance within populations, shown to be significant, was 62.78% (p＜0.001). The results indicated that there is a considerable genetic diversification among river systems, and most of the diversification was between populations. Based on our mantel test, correlation coefficients among genetic variation among for 18 natural populations were significant, influenced by the geographical distribution but uninfluenced by the elevation. The cluster analysis and principal coordinate analysis revealed two major general groupings of northern and central-southern groups. The Gao-ping-shi river system was found to be a relatively isolated group by the cluster analysis. Cluster analysis and principal coordinate analysis (PCOA) also revealed that the genetic differentiation may be caused by different environments.

並列關鍵字

Broussonetia papyrifera Vent ； ISSR ； genetic diversity ； gene flow ； genetic variation