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.

中文翻译：

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酵母中的非整倍性：分离错误还是适应机制？

非整倍性是基因组内染色体的丢失或增加。它通常是有害的，并且与细胞死亡和遗传性疾病有关。然而，非整倍性也可能是有益的，并且当细胞面临环境压力时，通过改变基因剂量提供快速解决方案。在这里，我们回顾了酵母菌、念珠菌和隐球酵母（及其杂交后代）中非整倍体的流行情况，并分析了与染色体大小和特定应激源的关联。我们讨论非整倍性（一种分离错误）实际上如何为微生物的多样化提供一条自然途径，并在适当的生态环境下实现重要的进化创新，例如新环境的殖民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和非整倍性之间很大程度上未经研究的交叉联系。杂交减数分裂涉及两个不同的基因组，由于抗重组和染色体错误分离，可能导致后代非整倍体率急剧增加。由于杂交和非整倍性都已被证明会随着环境压力而增加，因此我们认为开始探索它们共现的进化意义是重要且及时的。