GENETIC DIVERSITY AND POPULATION STRUCTURE IN CAMELLIA JAPONICA L. (THEACEAE)
GENETIC DIVERSITY AND POPULATION STRUCTURE IN CAMELLIA JAPONICA L. (THEACEAE)
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山茶科（茶科）遗传多样性和种群结构
DOI：
10.1002/j.1537-2197.1985.tb05344.x
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发表时间：
1985
影响因子：
3
通讯作者：
C. R. Parks
中科院分区：
文献类型：
--
作者：
J. Wendel;C. R. Parks
山茶是一种分布广泛，形态多样的树木，原产于日本部分地区和邻近岛屿。淀粉凝胶电泳被用来评分等位基因变异在20个位点的种子收集来自60个群体分布在整个物种范围。与其它植物种相比，苦草的遗传多样性水平较高。japonicapoluments是非常高的：平均每个群体有66.2%的位点是多态的，平均每个位点有2.16个等位基因，平均观察杂合度为0.230，平均泛混杂合度为0.265。大多数群体中大多数位点的基因型比例符合哈代温伯格的预期。然而，小杂合子的缺陷，通常观察到（平均人口固定指数= 0.129）。结果表明，种群分化的总体水平高于在异交种中通常观察到的水平：成对种群之间的平均遗传距离和同一性（Nei's D和I）分别为0.073和0.930，Wright's Fst为0.144。种群间的差异表现为在许多位点的基因频率的变化，而不是等位基因组成本身的变化。然而，变异的模式不是随机的。在6个位点上观察到等位基因对的基因频率的相互倾斜变化。此外，主成分分析显示，人口倾向于遗传聚类到四个地区代表的地理区域九州，四国，本州西部，本州东部。遗传距离与地理距离呈显著正相关（r = 0.61; P < 0.01）。等位酶频率的方差分析表明，区域内种群间的分化是区域间的4倍。观察到的种群关系模式很可能是由于小型亚种群的遗传漂变和它们之间的基因流动之间的平衡。
Camellia japonicais a widespread and morphologically diverse tree native to parts of Japan and adjacent islands. Starch gel electrophoresis was used to score allelic variation at 20 loci in seeds collected from 60 populations distributed throughout the species range. In comparison with other plant species, the level of genetic diversity withinC. japonicapopulations is very high: 66.2% of loci were polymorphic on average per population, with a mean number of 2.16 alleles per locus; the mean observed and panmictic heterozygosities were 0.230 and 0.265, respectively. Genotypic proportions at most loci in most populations fit Hardy‐Weinberg expectations. However, small heterozygote deficiencies were commonly observed (mean population fixation index = 0.129). It is suggested that the most likely cause of the observed deficiencies is population subdivision into genetically divergent subpopulations.The overall level of population differentiation is greater than is typically observed in out‐breeders: The mean genetic distance and identity (Nei's D and I) between pairs of populations were 0.073 and 0.930, respectively, and Wright's Fst was 0.144. Differences among populations appeared to be manifested as variation in gene frequencies at many loci rather than variation in allelic composition per se. However, the patterns of variation were not random. Reciprocal clinal variation of gene frequencies was observed for allele pairs at six loci. In addition, principal components analysis revealed that populations tended to genetically cluster into four regions representing the geographic areas Kyushu, Shikoku, western Honshu, and eastern Honshu. There was a significant relationship between genetic and geographic distance (r = 0.61; P < 0.01). Analysis of variance on allozyme frequencies showed that there was approximately four times as much differentiation among populations within regions, as among regions. It is likely that the observed patterns of population relationships result from the balance between genetic drift in small subpopulations and gene flow between them.