摘要
采用空间自相关分析方法对准噶尔无叶豆(Eremosparton songoricum)5个居群遗传变异的空间结构进行了研究。根据8对ISSR引物扩增的多态性位点,选择了基因频率在30–70%的ISSR位点,运用GenAlEx6和SAAP4.3软件以及地理距离间隔方法分别计算了5个居群的空间自相关系数。结果表明:准噶尔无叶豆居群具有明显的空间遗传结构,绝大多数ISSR位点变异呈非随机分布。位于沙漠腹地的B、D居群和位于沙漠东缘的F居群的遗传变异呈现渐变模式,分别在7m,7m及9m范围内个体呈现显著正相关,推测与克隆繁殖占绝对优势、有性更新罕见发生有关,而克隆大小的差别则主要由微生境差异所引起。位于沙漠北缘的G居群的遗传变异呈现双向渐变模式,在3m内个体呈现显著正相关,这与该居群实生幼苗增补密切相关,但花粉和种子的有限散布所导致的距离隔离对该居群空间遗传结构产生了重要影响。而沙漠腹地的A居群呈现衰退模式,是因为小居群增加了近交的几率,并引起了遗传漂变。
Spatial autocorrelation analyses have highlighted the importance of clonal growth in shaping the spatial genetic structure in Eremosparton songoricum, a woody rhizomatic clonal shrub distributed in drift sand dunes of the Gurbantunggut Desert of China. Spatial patterns of genetic variation in five populations of E. songoricum found in different community types and habitats were investigated using Inter Simple Se- quence Repeat （ISSR） markers. Using GeneAlEx Genetic Analysis Software and the computer program of SAAP 4.3 and the polymorphic bands generated from eight ISSR primers, we calculated an autocorrelation coefficient with a frequency between 0.3 and 0.7. Equal geographic distance was considered when estimating spatial genetic distribution patterns. In this paper, populations B （located in hinterland desert）, D （located in hinterland desert） and F （located in east of desert） occurred as a cline pattern, in which individual plants within distances of 7 m, 7 m and 9 m had significant positive correlation, respectively. Our results suggested that the natural properties of clonal reproduction were the main factors influencing the spatial distribution patterns of these three populations. Population G （located in north of desert） occurred as double cline pattern, in which individual plants within 3 m had significant positive correlation, respectively. Seed recruitment was successful in population G, while restricted seed and pollen dispersal, and intervention of human activities were main factors influencing the spatial genetic structure. Population A （located in hinterland desert） ex-hibited depression pattern. The small size of population A would increase the likelihood of self-fertilization （inbreeding） by pollination among ramets of the same genets, and would induce random genetic drift. Knowledge of spatial genetic structures within populations is crucial for understanding evolutionary processes and ecological adaptations, and provides a baseline for the conservation and management of E. songoricum, especially for ex situ conservation sampling strategies.
出处
《生物多样性》
CAS
CSCD
北大核心
2010年第2期129-136,共8页
Biodiversity Science
基金
国家自然科学基金项目(30970547)
新疆科技厅科技支撑计划项目(200933122)
重大专项项目(200731138-3)
