Yeager Randi, Heasley Lydia, Baker Nolan, Shrivastava Vatsal, Woodman Julie, McMurray Michael
Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA.
Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, Colorado, USA.
bioRxiv. 2024 Jul 3:2024.06.27.601111. doi: 10.1101/2024.06.27.601111.
Features of the natural life cycle of the budding yeast were crucial to its domestication as a laboratory experimental model, especially the ability to maintain stable haploid clones and cross them at will to combine alleles via meiosis. Stable haploidy results from mutations in , which encodes an endonuclease required for haploid-specific mating-type switching. Previous studies found an unexpected diversity of alleles among natural isolates within a small geographic area. We developed a hands-on field and laboratory activity for middle school students in Denver, Colorado, USA to isolate wild yeast from oak bark, identify species via DNA sequencing, and sequence from isolates. We find limited diversity in North American oak isolates, pointing to efficient, continuous dispersal across the continent. By contrast, we isolated the "dairy yeast", , from a tree <10 m away and found that it represents a new population distinct from an oak population in an adjacent state, pointing to high genetic diversity. The outreach activity partnered middle school, high school, and university students in making scientific discoveries and can be adapted to other locations and natural yeast habitats. Indeed, a pilot sampling activity in southeast Texas yielded oak isolates with a new allele of and, from a nearby prickly pear cactus, a heat-tolerant isolate of .
芽殖酵母自然生命周期的特征对其作为实验室实验模型的驯化至关重要，特别是维持稳定单倍体克隆并随意杂交以通过减数分裂组合等位基因的能力。稳定的单倍体状态源于编码单倍体特异性交配型转换所需内切核酸酶的基因突变。先前的研究发现，在一个小地理区域内的自然分离株中，该基因的等位基因存在意想不到的多样性。我们为美国科罗拉多州丹佛市的中学生开展了一项实践活动，包括从橡树树皮中分离野生酵母、通过DNA测序鉴定物种以及对分离株的该基因进行测序。我们发现北美橡树分离株中的该基因多样性有限，这表明其在整个大陆进行了高效、持续的传播。相比之下，我们从一棵距离不到10米的树上分离出了“乳酒酵母”，并发现它代表了一个与相邻州的橡树群体不同的新群体，这表明其具有高遗传多样性。这项外展活动让中学生、高中生和大学生共同参与科学发现，并且可以适用于其他地点和自然酵母栖息地。事实上，在得克萨斯州东南部的一项试点采样活动中，从橡树中分离出了具有该基因新等位基因的菌株，并且从附近的仙人掌中分离出了耐热的该酵母菌株。
