FAW: Molecular Studies on the Evolution and Development of Pteridophytes

蕨类植物是进化和发育研究的理想选择。追踪蕨类植物进化的分子研究尤其重要，因为用于系统研究的形态特征很少，而且分类学家对某些特征的统一性存在分歧。在这项研究中，研究者将研究几种蕨类植物的基因组组织。由于遗传距离太大，限制性内切位点突变的比较被排除在外，因此基因组重排对于确定高阶分类上的连锁是有价值的。人们很可能通过寻找直接介于原始蕨类>Osmunda>和高等蕨类之间的代表来追踪这种重排的进化。研究者将收集和分析旧大陆树蕨的叶绿体DNA突变，并将这些结果与新大陆树蕨的数据进行比较。目前有一种假说得到了被子植物研究的一些支持，即来自旧世界和新世界的物种看起来相似，而不是彼此接近的不同物种。上述研究将解决这一问题。蕨类植物也为研究基因调控提供了几个潜在的有价值的特征。单倍体一代是一个小的，完全独立的植物，从一个单细胞（孢子）生长，可以是两性。与开花植物不同，自交受精在一代内产生100%纯合子的二倍体植物。孢子的转化将使研究者能够产生与引入性状纯合子的植株。将被检查的特定基因是决定男性的基因。某些物种的孢子在激素花药原存在的情况下发芽，产生雄性单倍体植物。这表明，在这种激素的作用下，一个不同的基因被激活，而不是在没有激素的情况下播种孢子，并与其他配子体分离。减法杂交将用于富集与这两种不同发育途径相关的特定信息。

Ferns are ideal for evolutionary and developmental studies. Molecular studies tracing fern evolution are especially important because there is a paucity of morphological characters for use in systematic studies and taxonomists disagree about the unity of some traits. In this research, the investigator will study the organization of the genomes in several fern families. Genome rearrangements are valuable for determining linkage at higher orders of taxonomic classification where comparisons of restriction site mutations are precluded because the genetic distance is too great. It is likely that one could trace the evolution of the rearrangements by finding representatives that are immediate between the primitive fern >Osmunda> and the higher ferns. The investigator will collect and analyze the old world tree ferns for chloroplast DNA mutations and compare these results to data on new world tree ferns. One current hypothesis, which has some support from angiosperm studies, is that species from the old and new worlds that look alike differ more than different species which are in close proximity to each other. The study described would address this issue. Ferns also offer several potentially valuable features for studying gene regulation. The haploid generation is a small, fully independent plant that grows from a single cell (the spore) and can be bisexual. Unlike flowering plants, self fertilization produces a diploid plant that is 100% homozygous in one generation. Transformation of the spore will allow the investigator to generate plants homozygous for the introduced trait. The particular genes that will be examined are male determining genes. Spores of certain species that are sown in the presence of the hormone antheridiogen germinate to produce a male haploid plant. This suggests that a different gene(s) is activated in response to this hormone than when the spore is sown without the hormone and in isolation from other gametophytes. Subtraction hybridization will be used to enrich for specific messages related to these two different developmental pathways.