The Structure and Function of Sex Chromosomes in Plants

稳定的性别决定遗传机制是维持物种中不同性别的先决条件。这反过来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不常见，在动物中广泛存在，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近，这意味着在许多情况下，也存在缺乏性染色体的密切相关物种。在亲缘关系密切的植物群体中，性染色体分化变异的存在为研究性染色体起源提供了模式系统。我们正在研究硅烯中的Y染色体，以验证有关其结构和功能的理论预测。用流式细胞术从分离的Silene Alba的Y染色体中建立DNA文库，这是一项应用于人类基因组的巨大成功的技术。由此产生的Y-特异性DNA探针将与白纹伊蚊的雄性和雌性以及其他近亲的染色体进行交叉杂交。我们的预期是，Y染色体将有一些在结构上类似于X的区域。结构不同区域的存在有助于防止重组，而重组会破坏在Silene中发现的“活性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.