Institute of Bioinformatics and Department of Plant Biology, University of Georgia, Athens, GA 30602, USA.
Laboratory of Genetics and Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison, WI 53706, USA.
Genetics. 2021 Apr 15;217(4). doi: 10.1093/genetics/iyab015.
Individuals carrying an aberrant number of chromosomes can vary widely in their expression of aneuploidy phenotypes. A major unanswered question is the degree to which an individual's genetic makeup influences its tolerance of karyotypic imbalance. Here we investigated within-species variation in aneuploidy prevalence and tolerance, using Saccharomyces cerevisiae as a model for eukaryotic biology. We analyzed genotypic and phenotypic variation recently published for over 1,000 S. cerevisiae strains spanning dozens of genetically defined clades and ecological associations. Our results show that the prevalence of chromosome gain and loss varies by clade and can be better explained by differences in genetic background than ecology. The relationships between lineages with high aneuploidy frequencies suggest that increased aneuploidy prevalence emerged multiple times in S. cerevisiae evolution. Separate from aneuploidy prevalence, analyzing growth phenotypes revealed that some genetic backgrounds-such as the European Wine lineage-show fitness costs in aneuploids compared to euploids, whereas other clades with high aneuploidy frequencies show little evidence of major deleterious effects. Our analysis confirms that chromosome gain can produce phenotypic benefits, which could influence evolutionary trajectories. These results have important implications for understanding genetic variation in aneuploidy prevalence in health, disease, and evolution.
个体携带异常数量的染色体，在表现非整倍体表型方面可能存在很大差异。一个尚未解决的主要问题是，个体的遗传构成在多大程度上影响其对染色体不平衡的耐受能力。在这里，我们使用酿酒酵母作为真核生物学的模型，研究了非整倍体流行率和耐受性的种内变异。我们分析了最近发表的超过 1000 株酿酒酵母菌株的基因型和表型变异，这些菌株跨越了几十个遗传定义的进化枝和生态关联。我们的结果表明，染色体获得和丢失的流行率因进化枝而异，并且可以通过遗传背景的差异而不是生态来更好地解释。具有高非整倍体频率的谱系之间的关系表明，在酿酒酵母进化过程中，非整倍体的流行率多次增加。除了非整倍体流行率之外，分析生长表型表明，一些遗传背景，如欧洲葡萄酒谱系，与整倍体相比，在非整倍体中表现出适应性成本，而其他具有高非整倍体频率的进化枝几乎没有证据表明存在主要的有害影响。我们的分析证实，染色体获得可以产生表型益处，这可能会影响进化轨迹。这些结果对于理解健康、疾病和进化中非整倍体流行率的遗传变异具有重要意义。
