POLYMORPHIC SIMPLE SEQUENCE REPEAT REGIONS IN CHLOROPLAST GENOMES - APPLICATIONS TO THE POPULATION-GENETICS OF PINES
POLYMORPHIC SIMPLE SEQUENCE REPEAT REGIONS IN CHLOROPLAST GENOMES - APPLICATIONS TO THE POPULATION-GENETICS OF PINES
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DOI：
10.1073/pnas.92.17.7759
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发表时间：
1995-08-15
影响因子：
11.1
通讯作者：
RAFALSKI, JA
中科院分区：
文献类型：
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作者：
POWELL, W;MORGANTE, M;RAFALSKI, JA
简单序列重复序列(SSRs)是真核生物基因组中普遍存在的一种常见的遗传标记。利用其长度的多态，我们研究了植物叶绿体基因组中这类序列的多态性。通过基于聚合酶链式反应的分析，GenBank检索到叶绿体基因组中存在几个(Da)(N).(Dt)(N)在叶绿体基因组中存在(Dt)(N)单核苷酸片段，在3个松种(赤松、樟子松和赤松)中发现了一个叶绿体SSR对11种松树的叶绿体基因组进行DNA扩增，鉴定出9个长度变异，分离出多态的扩增片段并测定DNA序列，证实了长度多态是由重复区长度的变异引起的。在松树中，叶绿体基因组是通过花粉传递的，该方法可用于监测松属植物的基因流动。白皮松7个居群305株个体分析揭示了四个变异的存在，种群内多样性从0.000到0.629不等，平均为0.320。同一居群的cpDNA限制性内切酶片段长度多态性分析没有检测到任何变异，基于cpSSR的居群划分(G(St)=0.22，其中G(St)为基因分化系数)高于先前同工酶研究的结果(G(St)=0.05)。我们预计，叶绿体基因组中的SSR基因座将为分析植物居群的遗传结构提供一种信息丰富的分析方法。
Simple sequence repeats (SSRs), consisting of tandemly repeated multiple copies of mono-, di-, tri-, or tetranucleotide motifs, are ubiquitous in eukaryotic genomes and are frequently used as genetic markers, taking advantage of their length polymorphism, We have examined the polymorphism of such sequences in the chloroplast genomes of plants, by using a PCR-based assay, GenBank searches identified the presence of several (dA)(n) .(dT)(n) mononucleotide stretches in chloroplast genomes, A chloroplast (cp) SSR was identified in three pine species (Pinus contorta, Pinus sylvestris, and Finns thunbergii) 312 bp upstream of the psbA gene, DNA amplification of this repeated region from 11 pine species identified nine length variants, The polymorphic amplified fragments were isolated and the DNA sequence was determined, confirming that the length polymorphism was caused by variation in the length of the repeated region, In the pines, the chloroplast genome is transmitted through pollen and this PCR assay may be used to monitor gene flow in this genus. Analysis of 305 individuals from seven populations of Pinus leucodermis Ant. revealed the presence of four variants with intrapopulational diversities ranging from 0.000 to 0.629 and an average of 0.320. Restriction fragment length polymorphism analysis of cpDNA on the same populations previously failed to detect any variation, Population subdivision based on cpSSR was higher (G(st) = 0.22, where G(st) is coefficient of gene differentiation) than that revealed in a previous isozyme study (G(st) = 0.05) We anticipate that SSR loci within the chloroplast genome should provide a highly informative assay for the analysis of the genetic structure of plant populations.