A global analysis of ploidy maintenance in S. cerevisiae

在细胞中，遗传物质（DNA）储存在称为染色体的复杂结构中。每个生物体都有特定数量的染色体，这在生物体的所有细胞中都是恒定的（有一些例外，比如生殖细胞——例如人类的卵子和精子）。细胞包含完整的DNA拷贝，并将其包装成正确数量的染色体，这对细胞的正常功能至关重要。不幸的是，当一个细胞生长并分裂成两个细胞时，这给细胞带来了一个问题：如何确保两个子细胞都有正确数量的染色体？为了完成这一壮举，细胞首先复制它们所有的DNA，使它们包含两条染色体，然后在子细胞之间精确地划分染色体。我们正在研究在简单的单细胞生物酿酒酵母（面包酵母）中，染色体的正确数目是如何在细胞生长和分裂时维持的。相对于植物或动物等更复杂的生物，这种有机体的简单性使其成为解决生物问题的一个很好的系统，因为它的系统通常更紧凑和流线型（它们的“部件”更少）。尽管如此简单，但重要生物系统的类似版本在进化过程中是保守的，因此通常存在于所有生物体中，从最简单的到最复杂的。了解基本过程背后的生物学原理，比如简单生物体中染色体的恒定数量，就可以应用于了解植物和多细胞动物的相同过程。我们的研究有潜力确定酵母中所有有助于维持恒定和准确染色体数目的系统。这将是第一次对这一过程进行如此完整的描述，对于研究细胞生长和分裂的科学家，以及对染色体数目差异如何影响细胞功能感兴趣的科学家来说，这将是有用的。

In cells the genetic material (DNA) is stored in complex structures called chromosomes. Every organism has a specific number of chromosomes, and this is constant in all cells in the organism (with some exceptions, such as germ cells-for example, eggs and sperm in humans). It is essential for the proper function of a cell that it contains a complete copy of the DNA, packaged into the correct number of chromosomes. Unfortunately, this poses a problem for cells when one cell grows and divides to form two cells: How to make sure that both daughter cells have the correct number of chromosomes? To accomplish this feat, cells first copy all of their DNA so that they contain two of each chromosome, and then the chromosomes are divided accurately between the daughter cells. We are studying how the correct number of chromosomes is maintained as cells grow and divide, in the simple single-cell organism Saccharomyces cerevisiae (baker's yeast). The simplicity of this organism, relative to more complicated ones like plants or animal, makes it a good system for figuring out biological problems, since its systems are typically more compact and streamlined (they have fewer "parts"). Despite this simplicity, similar versions of important biological systems are conserved during evolution, and so are typically present in all organisms, from the simplest to the most complex. Understanding the biology behind fundamental processes like the constant number of chromosomes in a simple organism can then be applied to understanding the same process in, for example, plants and multicellular animals. Our study has the potential to identify all of the systems in yeast that contribute to maintaining a constant and accurate chromosome number. This will be the first time such a complete description of the process has been furnished, and will be of use to scientists studying cell growth and division, and those interested in how differences in chromosome number can affect cellular function.