Maize is one of the world's most important crops and a model for grass genome research. Long terminal repeat (LTR) retrotransposons comprise most of the maize genome; their ability to produce new copies makes them efficient high-throughput genetic markers. Inter-retrotransposon-amplified polymorphisms (IRAPs) were used to study the genetic diversity of maize germplasm. Five LTR retrotransposons (Huck, Tekay, Opie, Ji, and Grande) were chosen, based on their large number of copies in the maize genome, whereas polymerase chain reaction primers were designed based on consensus LTR sequences. The LTR primers showed high quality and reproducible DNA fingerprints, with a total of 677 bands including 392 polymorphic bands showing 58% polymorphism between maize hybrid lines. These markers were used to identify genetic similarities among all lines of maize. Analysis of genetic similarity was carried out based on polymorphic amplicon profiles and genetic similarity phylogeny analysis. This diversity was expected to display ecogeographical patterns of variation and local adaptation. The clustering method showed that the varieties were grouped into three clusters differing in ecogeographical origin. Each of these clusters comprised divergent hybrids with convergent characters. The clusters reflected the differences among maize hybrids and were in accordance with their pedigree. The IRAP technique is an efficient high-throughput genetic marker-generating method.

中文翻译：

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基于高通量反转录转座子的玉米种质遗传多样性评估与分析。

玉米是世界上最重要的农作物之一，也是草基因组研究的模型。长末端重复（LTR）逆转座子构成了大多数玉米基因组。它们产生新拷贝的能力使它们成为高效的高通量遗传标记。逆转录转座子间扩增多态性（IRAPs）用于研究玉米种质的遗传多样性。根据其在玉米基因组中的大量拷贝，选择了五个LTR反转录转座子（Huck，Tekay，Opie，Ji和Grande），而基于共有LTR序列设计了聚合酶链反应引物。LTR引物显示出高质量和可再现的DNA指纹，共有677个条带，其中392个多态性条带显示了玉米杂交品系之间58％的多态性。这些标记用于鉴定玉米所有品系之间的遗传相似性。基于多态性扩增子谱和遗传相似性系统发育分析，进行遗传相似性分析。预期这种多样性将显示变异和局部适应的生态地理模式。聚类方法表明，该品种被分为三个地理地理来源不同的簇。这些集群中的每一个都包含具有收敛特征的发散杂种。这些簇反映了玉米杂交种之间的差异，并且符合其谱系。IRAP技术是一种高效的高通量遗传标记生成方法。预期这种多样性将显示变异和局部适应的生态地理模式。聚类方法表明，该品种被分为三个地理地理来源不同的簇。这些集群中的每一个都包含具有收敛特征的发散杂种。这些簇反映了玉米杂交种之间的差异，并且符合其谱系。IRAP技术是一种高效的高通量遗传标记生成方法。预期这种多样性将显示变异和局部适应的生态地理模式。聚类方法表明，该品种被分为三个地理地理来源不同的簇。这些集群中的每一个都包含具有收敛特征的发散杂种。这些簇反映了玉米杂交种之间的差异，并且符合其谱系。IRAP技术是一种高效的高通量遗传标记生成方法。