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。每个有机体都有特定数量的染色体，这在有机体中的所有细胞中都是恒定的(除了一些例外，比如生殖细胞--例如人类的卵子和精子)。对于细胞的正常功能来说，它包含一个完整的DNA拷贝，并打包到正确数量的染色体中，这是必不可少的。不幸的是，当一个细胞生长并分裂形成两个细胞时，这给细胞带来了一个问题：如何确保两个子细胞都有正确的染色体数量？为了完成这一壮举，细胞首先复制它们的所有DNA，使它们包含每条染色体的两条，然后在子细胞之间准确地划分染色体。我们正在研究在简单的单细胞生物酿酒酵母(面包酵母)中，当细胞生长和分裂时，如何保持正确的染色体数量。与植物或动物等更复杂的生物体相比，这种生物体的简单性使其成为解决生物问题的好系统，因为它的系统通常更紧凑和流线型(它们有更少的“部件”)。尽管这种简单性，但重要生物系统的相似版本在进化过程中是保守的，因此从最简单到最复杂的所有生物体中通常都存在这种情况。理解简单有机体中染色体数量恒定等基本过程背后的生物学原理，就可以用来理解同样的过程，例如植物和多细胞动物。我们的研究有可能确定酵母中有助于保持恒定和准确的染色体数量的所有系统。这将是第一次提供对这一过程的如此完整的描述，将对研究细胞生长和分裂的科学家以及那些对染色体数量差异如何影响细胞功能感兴趣的科学家有用。

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.