Pears (Pyrus) are one of the most economically important fruits worldwide. The Pyrus genus is characterized by a high degree of genetic variability between species and interspecific hybrids, and several studies have been performed to assess this variability for both cultivated and wild accessions. These studies have mostly been limited by the resolving power of traditional molecular markers, although in the recent past the availability of reference genome sequences or SNP arrays for pear have enhanced the capability of high-resolution genomics studies. These tools can also be applied to better understand the intra-varietal (or clonal) variability in pear. Here we report the first high resolution genomics analysis of a pear clonal population using whole genome sequencing (WGS). Results showed unique signatures for the accumulation of mutations and transposable element insertions in each clone, which are likely related to their history of propagation and cultivation. The nucleotide diversity remained low in the clonal collection with the exception of few genomic windows, suggesting that balancing selection may be occurring. These windows included mainly genes related to plant fertility. Regions with higher mutational load were partially associated with transcription factors, probably reflecting the distinctive phenotypes in the collection. The annotation of variants also revealed the theoretical disruption of relevant genes in pear. Taken together, the results from this study show that pear clones accumulate mutations differently, and that those mutations can play a role on pear phenotypes, meaning that the study of pear clonal populations can be relevant in genetic studies, mainly when comparing with traditional association studies.

中文翻译：

---

使用高通量测序对欧洲梨“Rocha”进行全基因组克隆变异性分析

梨（Pyrus）是世界上最重要的经济水果之一。Pyrus 属的特征是物种和种间杂种之间的高度遗传变异性，并且已经进行了几项研究来评估栽培和野生种质的这种变异性。这些研究大多受到传统分子标记的分辨能力的限制，尽管在最近过去，梨的参考基因组序列或 SNP 阵列的可用性增强了高分辨率基因组学研究的能力。这些工具还可用于更好地了解梨的品种内（或克隆）变异性。在这里，我们报告了使用全基因组测序 (WGS) 对梨克隆种群进行的第一次高分辨率基因组学分析。结果显示每个克隆中突变积累和转座因子插入的独特特征，这可能与它们的繁殖和培养历史有关。除了少数基因组窗口外，克隆集合中的核苷酸多样性仍然很低，这表明可能正在发生平衡选择。这些窗口主要包括与植物生育力相关的基因。具有较高突变负荷的区域与转录因子部分相关，可能反映了该集合中的独特表型。变异的注释还揭示了梨中相关基因的理论破坏。综上所述，这项研究的结果表明，梨克隆积累的突变不同，这些突变可以在梨表型中发挥作用，