Okuno Miki, Kajitani Rei, Ryusui Rie, Morimoto Hiroya, Kodama Yukiko, Itoh Takehiko
Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan.
Suntory Global Innovation Center Limited, 8-1-1 Seikadai, Seika-cho, Soraku-gun, Kyoto 619-0284, Japan.
DNA Res. 2016 Feb;23(1):67-80. doi: 10.1093/dnares/dsv037. Epub 2016 Jan 4.
The lager beer yeast Saccharomyces pastorianus is considered an allopolyploid hybrid species between S. cerevisiae and S. eubayanus. Many S. pastorianus strains have been isolated and classified into two groups according to geographical origin, but this classification remains controversial. Hybridization analyses and partial PCR-based sequence data have indicated a separate origin of these two groups, whereas a recent intertranslocation analysis suggested a single origin. To clarify the evolutionary history of this species, we analysed 10 S. pastorianus strains and the S. eubayanus type strain as a likely parent by Illumina next-generation sequencing. In addition to assembling the genomes of five of the strains, we obtained information on interchromosomal translocation, ploidy, and single-nucleotide variants (SNVs). Collectively, these results indicated that the two groups of strains share S. cerevisiae haploid chromosomes. We therefore conclude that both groups of S. pastorianus strains share at least one interspecific hybridization event and originated from a common parental species and that differences in ploidy and SNVs between the groups can be explained by chromosomal deletion or loss of heterozygosity.
拉格啤酒酵母巴氏酵母被认为是酿酒酵母和真贝氏酵母之间的异源多倍体杂交物种。许多巴氏酵母菌株已被分离出来，并根据地理来源分为两组，但这种分类仍存在争议。杂交分析和基于部分PCR的序列数据表明这两组有不同的起源，而最近的染色体间易位分析则表明是单一起源。为了阐明该物种的进化历史，我们通过Illumina下一代测序分析了10个巴氏酵母菌株和作为可能亲本的真贝氏酵母模式菌株。除了组装其中五个菌株的基因组外，我们还获得了关于染色体间易位、倍性和单核苷酸变异（SNV）的信息。总体而言，这些结果表明两组菌株共享酿酒酵母单倍体染色体。因此，我们得出结论，两组巴氏酵母菌株至少共享一次种间杂交事件，并且起源于一个共同的亲本物种，两组之间倍性和SNV的差异可以通过染色体缺失或杂合性丧失来解释。
