Soybean breeding relies on the use of wild (Glycine soja Sieb. and Zucc.) and domesticated [Glycine max (L.) Merr.] germplasm for trait improvement. Soybeans are self‐pollinating and accessions can be maintained as pure lines, however within‐accession genetic variation has been observed in previous studies of some landraces and elite cultivars. The objective of this study was to characterize within‐line variation in the accessions housed in the USDA Soybean Germplasm Collection. This collection includes over 20,000 accessions, each previously genotyped using the SoySNP50K Chip. Each SoySNP50K genotype was developed by pooling approximately three individuals per accession. Therefore, clusters of SNPs called as heterozygous within an accession can be inferred to represent putative regions of heterogeneity between the three individuals sampled. In this study, we found high‐probability intervals of heterogeneity in 4% of the collection, representing 870 accessions. Heterogeneous loci were found on every chromosome and, collectively, covered 98.4% of the soybean genome and 99% of the gene models. Sanger sequencing confirmed regions of genomic heterogeneity among a subset of ten accessions. This dataset provides useful information and considerations for users of crop germplasm seed banks. Furthermore, the heterogeneous accessions and/or loci represent a unique genetic resource that is immediately available for forward and reverse genetics studies.

中文翻译：

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USDA大豆种质资源中种质内遗传异质性的特征

大豆的育种依赖于野生（甘氨酸大豆）和驯养[ Glycine max[L.）Merr。]种质改良。大豆是自花授粉的，种质可以保持纯系，但是在先前的一些地方品种和优良品种研究中，种内种质遗传变异。这项研究的目的是表征USDA大豆种质资源库中保存的种质的种内差异。该集合包括20,000多个登录号，每个登录号以前都使用SoySNP50K芯片进行了基因分型。每个SoySNP50K基因型是通过每个登录集中约3个个体而开发的。因此，可以推断出一个登录物中称为杂合子的SNP簇，以代表三个样本个体之间的假定异质性区域。在这项研究中，我们发现4％的馆藏存在高概率的异质性，代表870个加入。在每个染色体上均发现了异源位点，这些位点共同覆盖了98.4％的大豆基因组和99％的基因模型。Sanger测序证实了十个种质子集之间的基因组异质性区域。该数据集为作物种质种子库的用户提供了有用的信息和注意事项。此外，异质种质和/或基因座代表了独特的遗传资源，可立即用于正向和反向遗传学研究。