中国杯萼海桑遗传多样性的ISSR研究

杯萼海桑(Sonneratia alba J.Smith.)是海桑科红树植物,在我国分布于海南岛的东海岸.本文采用简单序列霞复区间扩增(ISSR)分子标记技术对分布于海南岛的杯萼海桑的4个天然居群和东寨港红树林自然保护区引种的一人工居群共100个个体进行了遗传变异分析.11个引物共扩增出133条带,其中103条具多态性,多态位点百分率为77.44%.在居群水平上相对较低,多态位点百分率为51.88%～65.41%,平均为57.74%.期望杂合度、香农信息指数在物种水平上分别为0.227 1和0.348 9;在居群水平上分别为0.1 83 7和0.227 5.依据Gst值,杯萼海桑绝大多数遗传变异发生在居群内的个体间(81.02%),18.98%的遗传变异发生在居群间.AMOVA分析也表明了类似的遗传结构.居群间平均遗传一致度为0.934 2.依据Nei(1972)的遗传距离对不同居群进行UPGMA聚类,将居群分为两组,来自三亚(SY)和陵水(LS)的居群聚为一类;东寨港引种栽培的人工居群(DZ)和琼海(QH)、文昌(WC)的居群聚为另一类.Mantel检验表明,遗传距离与地理距离呈极显著相关.

Genetic Diversity of Sonneratia alba in China Detected by Inter-simple Sequence Repeats (ISSR) Analysis

Sonneratia alba J.Smith is a widely distributed mangrove species. Leaf samples of one hundred individuals from four natural and one introduced populations in Hainan Island, China, were collected. Genetic variation among the five populations was evaluated using inter-simple sequence repeats (ISSR) markers. Eleven ISSR primers gave rise to 133 discernible DNA fragments of which 103 (77.44%) were polymorphic, indicating a considerable genetic variation at the species level. However, the polymorphism at the population level was relatively low, with the percentage of polymorphic bands from 51.88% to 65.41%. The mean expected heterozygosity and Shannon’s information index were 0.227 1 and 0.348 9 respectively at the species level, 0.183 7 and 0.277 5 at the population level. Based on Nei’s Gst value, a large proportion of genetic variance (81.02%) was resided among individuals within populations, however, only 18.98% genetic variance was resided among populations. AMOVA analysis also indicated a similar genetic structure. The genetic identity between populations was 0.934 2 on average. UPGMA cluster analysis based on Nei’s genetic distance divided the populations into two main groups: Linshui population (LS) and Sanya population (SY) formed one group, Qionghai population (QH), Wenchang population (WC) and Dongzhai Harbor population (DZ) were in the other group. The Mantel test showed that genetic distance was significantly correlated with geographical distance.