BACKGROUND Komagataella phaffii is a yeast widely used in the pharmaceutical and biotechnology industries, and is one of the two species that were previously called Pichia pastoris. However, almost all laboratory work on K. phaffii has utilized strains derived from a single natural isolate, CBS7435. There is little information about the sequence diversity of K. phaffii or the genetic properties of this species. RESULTS We sequenced the genomes of all the known isolates of K. phaffii. We made a genetic cross between derivatives of two isolates that differ at 44,000 single nucleotide polymorphism sites, and used this cross to analyze the rate and landscape of meiotic recombination. We conducted tetrad analysis by making use of the property that K. phaffii haploids do not mate in rich media, which enabled us to isolate and sequence the four types of haploid cell that are present in the colony that forms when a tetra-type ascus germinates. CONCLUSIONS We found that only four distinct natural isolates of K. phaffii exist in public yeast culture collections. The meiotic recombination rate in K. phaffii is approximately 3.5 times lower than in Saccharomyces cerevisiae, with an average of 25 crossovers per meiosis. Recombination is suppressed, and genetic diversity among natural isolates is low, in a region around centromeres that is much larger than the centromeres themselves. Our work lays a foundation for future quantitative trait locus analysis in K. phaffii.

中文翻译：

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生物技术酵母噬菌体（Komagataella phaffii，巴斯德毕赤酵母）分离株之间的基因组多样性和减数分裂重组。

背景技术Komagataella phaffii酵母是一种广泛用于制药和生物技术行业的酵母，并且是以前被称为巴斯德毕赤酵母的两个物种之一。但是，几乎所有有关K. phaffii的实验室工作都利用了衍生自单一天然分离株CBS7435的菌株。关于K.phaffii的序列多样性或该物种的遗传特性的信息很少。结果我们对所有已知的K. phaffii分离株的基因组进行了测序。我们在两个分离株的衍生物之间进行了遗传杂交，这些分离株在44,000个单核苷酸多态性位点不同，并使用该杂交来分析减数分裂重组的速率和态势。我们通过利用K. phaffii单倍体在丰富培养基中不交配的特性进行了四元分析，这使我们能够分离并测序在四型ascus萌发时形成的菌落中存在的四种类型的单倍体细胞。结论我们发现公共酵母培养物中仅存在四种不同的K. phaffii天然分离株。嗜酸K.phaffii的减数分裂重组率比酿酒酵母低约3.5倍，平均每个减数分裂有25次交换。在着丝粒周围的区域比着丝粒本身大得多的区域，重组受到抑制，自然分离株之间的遗传多样性低。我们的工作为今后在K. phaffii中进行定量性状基因座分析奠定了基础。phaffii存在于公共酵母培养物中。嗜酸K.phaffii的减数分裂重组率比酿酒酵母低约3.5倍，平均每个减数分裂有25次交换。在着丝粒周围的区域比着丝粒本身大得多的区域，重组受到抑制，自然分离株之间的遗传多样性低。我们的工作为今后在K. phaffii中进行定量性状基因座分析奠定了基础。phaffii存在于公共酵母培养物中。嗜酸K.phaffii的减数分裂重组率比酿酒酵母低约3.5倍，平均每个减数分裂有25次交换。在着丝粒周围的区域比着丝粒本身大得多的区域，重组受到抑制，自然分离株之间的遗传多样性低。我们的工作为今后在K. phaffii中进行定量性状基因座分析奠定了基础。