Division of Ecology and Evolutionary Biology, University of Glasgow, Glasgow G12 8QQ, UK.
J Evol Biol. 2010 Jul;23(7):1570-8. doi: 10.1111/j.1420-9101.2010.02012.x. Epub 2010 May 27.
In their recent article, Albertin et al. (2009) suggest an autotetraploid origin of 10 tetraploid strains of baker's yeast (Saccharomyces cerevisiae), supported by the frequent observation of double reduction meiospores. However, the presented inheritance results were puzzling and seemed to contradict the authors' interpretation that segregation ratios support a tetrasomic model of inheritance. Here, we provide an overview of the expected segregation ratios at the tetrad and meiospore level given scenarios of strict disomic and tetrasomic inheritance, for cases with and without recombination between locus and centromere. We also use a power analysis to derive adequate sample sizes to distinguish alternative models. Closer inspection of the Albertin et al. data reveals that strict disomy can be rejected in most cases. However, disomic inheritance with strong but imperfect preferential pairing could not be excluded with the sample sizes used. The possibility of tetrad analysis in tetraploid yeast offers a valuable opportunity to improve our understanding of meiosis and inheritance of tetraploids.
在他们最近的文章中，Albertin 等人（2009）提出了 10 株面包酵母（酿酒酵母）的四倍体菌株的自体四倍体起源，这一观点得到了双减数孢子经常观察的支持。然而，提出的遗传结果令人困惑，似乎与作者的解释相矛盾，即分离比支持四联体遗传模型。在这里，我们提供了在四分孢子和减数孢子水平上的预期分离比的概述，给出了严格的二倍体和四倍体遗传的情况，以及在基因座和着丝粒之间是否存在重组的情况。我们还使用幂分析来确定区分替代模型所需的足够样本量。对 Albertin 等人的数据进行更仔细的检查表明，在大多数情况下，可以拒绝严格的二倍体。然而，在使用的样本量下，不能排除具有强但不完全优先配对的二倍体遗传。在四倍体酵母中进行四分孢子分析为提高我们对四倍体减数分裂和遗传的理解提供了一个有价值的机会。
