Genome-wide characterization of genetic variants of a large population of individuals within the same species is essential to have a deeper insight into its evolutionary history as well as the genotype-phenotype relationship. Population genomic surveys have been performed in multiple yeast species, including the two model organisms, Saccharomyces cerevisiae and Schizosaccharomyces pombe. In this context, we sought to characterize at the population level the Brettanomyces bruxellensis yeast species, which is a major cause of wine spoilage and can contribute to the specific flavor profile of some Belgium beers. We have completely sequenced the genome of 53 B. bruxellensis strains isolated worldwide. The annotation of the reference genome allowed us to define the gene content of this species. As previously suggested, our genomic data clearly highlighted that genetic diversity variation is related to ploidy level, which is variable in the B. bruxellensis species. Genomes are punctuated by multiple loss-of-heterozygosity regions, whereas aneuploidies as well as segmental duplications are uncommon. Interestingly, triploid genomes are more prone to gene copy number variation than diploids. Finally, the pangenome of the species was reconstructed and was found to be small with few accessory genes compared with S. cerevisiae. The pangenome is composed of 5,409 ORFs (open reading frames) among which 5,106 core ORFs and 303 ORFs that are variable within the population. All these results highlight the different trajectories of species evolution and consequently the interest of establishing population genomic surveys in more populations.

中文翻译：

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Brettanomyces bruxellensis 种群的高度复杂性和遗传变异程度。

对同一物种内大量个体的遗传变异进行全基因组表征对于深入了解其进化历史以及基因型-表型关系至关重要。已在多种酵母物种中进行了种群基因组调查，包括两种模式生物，酿酒酵母和粟酒裂殖酵母。在这种情况下，我们试图在种群水平上对布鲁氏酒香酵母菌种进行表征，这是葡萄酒变质的主要原因，并可能导致某些比利时啤酒的特定风味特征。我们已经对全世界分离的 53 种布鲁塞尔芽孢杆菌菌株的基因组进行了完全测序。参考基因组的注释使我们能够定义该物种的基因含量。如前所述，我们的基因组数据清楚地强调了遗传多样性变异与倍性水平有关，这在 B. bruxellensis 物种中是可变的。基因组被多个杂合性缺失区域所打断，而非整倍体和节段重复并不常见。有趣的是，三倍体基因组比二倍体更容易发生基因拷贝数变异。最后，重建了该物种的泛基因组，发现与酿酒酵母相比，它的泛基因组很小，附属基因很少。泛基因组由 5,409 个 ORF（开放阅读框）组成，其中 5,106 个核心 ORF 和 303 个在种群内可变的 ORF。所有这些结果都突出了物种进化的不同轨迹，从而突出了在更多种群中建立种群基因组调查的兴趣。