Gilchrist Ciaran, Stelkens Rike
Division of Population Genetics, Department of Zoology, Stockholm University, Stockholm, Sweden.
Yeast. 2019 Sep;36(9):525-539. doi: 10.1002/yea.3427. Epub 2019 Aug 1.
Aneuploidy is the loss or gain of chromosomes within a genome. It is often detrimental and has been associated with cell death and genetic disorders. However, aneuploidy can also be beneficial and provide a quick solution through changes in gene dosage when cells face environmental stress. Here, we review the prevalence of aneuploidy in Saccharomyces, Candida, and Cryptococcus yeasts (and their hybrid offspring) and analyse associations with chromosome size and specific stressors. We discuss how aneuploidy, a segregation error, may in fact provide a natural route for the diversification of microbes and enable important evolutionary innovations given the right ecological circumstances, such as the colonisation of new environments or the transition from commensal to pathogenic lifestyle. We also draw attention to a largely unstudied cross link between hybridisation and aneuploidy. Hybrid meiosis, involving two divergent genomes, can lead to drastically increased rates of aneuploidy in the offspring due to antirecombination and chromosomal missegregation. Because hybridisation and aneuploidy have both been shown to increase with environmental stress, we believe it important and timely to start exploring the evolutionary significance of their co-occurrence.
非整倍体是指基因组内染色体的丢失或增加。它通常是有害的，与细胞死亡和遗传疾病有关。然而，非整倍体也可能是有益的，当细胞面临环境压力时，它可以通过基因剂量的变化提供一个快速的解决方案。在这里，我们综述了酿酒酵母、念珠菌和隐球菌酵母（及其杂交后代）中非整倍体的发生率，并分析了其与染色体大小和特定应激源的关联。我们讨论了非整倍体这种分离错误实际上如何为微生物的多样化提供一条自然途径，并在合适的生态环境下促成重要的进化创新，如新环境的定殖或从共生生活方式向致病生活方式的转变。我们还提请注意杂交与非整倍体之间一个很大程度上未被研究的交叉联系。涉及两个不同基因组的杂交减数分裂，由于抗重组和染色体错分离，可导致后代中非整倍体率急剧增加。由于杂交和非整倍体都已被证明会随着环境压力而增加，我们认为开始探索它们同时出现的进化意义既重要又及时。
