The Structure and Function of Sex Chromosomes in Plants

性别决定的稳定遗传机制是维持物种性别分离的先决条件。这反过来又要求那些促进或抑制女性和男性表达的基因位于同一染色体上。染色体性别决定在植物中并不常见，但在动物中广泛存在，并且几乎总是伴随着X和Y染色体的形态分化。植物中性染色体的起源相对较晚，这意味着在许多情况下，缺乏性染色体的近亲物种也存在。性染色体分化变异的存在为研究性染色体的起源提供了一个模式系统。我们正在研究Silene中的Y染色体，以测试有关其结构和功能的理论预测。利用流式细胞术分离的白硅烯的Y染色体将产生一个DNA文库，流式细胞术在人类基因组中取得了巨大的成功。所得到的y型特异性DNA探针将与雄性和雌性白棘虫以及其他近亲的染色体进行交叉杂交。我们的期望是Y染色体将有一些结构上与x相似的区域。结构上不同区域的存在有助于防止重组，从而破坏在Silene中发现的“主动Y”性别决定。

A stable genetic mechanism for sex determination is a prerequisite for the maintenance of separate sexes in a species. This in turn requires that those genes promoting or suppressing female and male expression be located on the same chromosome. Chromosomal sex determination, uncommon in plants, is widespread in animals and is almost invariably accompanied by morphological differentiation of the X and Y chromosomes. The relatively recent origin of sex chromosomes in plants means that, in many cases, closely related species which lack sex chromosomes, also exist. The existence of variation in sex chromosome differentiation within a closely related group of plants provides a model system for the study of the origin of sex chromosomes. We are studying Y chromosomes in Silene to test theoretical predictions concerning their structure and function. A DNA library will be generated from Y chromosomes of Silene alba isolated using flow cytometry, a technique applied with great success to the human genome. The resulting Y-specific DNA probes will be cross hybridized with chromosomes of male and female S. alba, as well as the other close relatives. Our expectation is that the Y chromosome will have some regions which are structurally similar to the X. The existence of structurally different regions serves to prevent recombination that would disrupt the "active Y" sex determination found in Silene.