Phylogenetic Relationships in Cheilanthoid Ferns (Adiantaceae) Based on Chloroplast DNA Restriction Site Variation and rbcL Sequence Data

大量的蕨类植物适应了半沙漠或 西南部和墨西哥的其他暴露条件 长期困惑的分类学家和生物学家， 系统发育关系和进化过程， 植物 有了分子分析的新生物技术工具， 印第安纳州大学的Gerald Gastony和乔治Yatskievych博士 正在研究植物叶绿体DNA的遗传变异 拟唇鱼属种代表标本 北美的蕨类植物来解决这个问题 因为DNA不受环境变化的影响 影响着茎、叶和生殖系统 结构是，比较核苷酸之间的差异 物种可以揭示物种的亲缘关系 考察 通过用酶消化叶绿体DNA， 在特定的核苷酸位点（所谓的 限制性位点酶，从细菌开发）比较 可以获得来自大量物种的数据。 他们的 初步数据显示， 位点变异性，表明广泛的突变差异 在物种之间。 计算机程序将被用来分析 数据，并将物种排列成最有可能进化的 根据它们共有的DNA特征进行分组。 这 然后，《遗传学》将允许详细分析以下过程： 在这些蕨类植物中， 适应性进化到恶劣的栖息地。

The large numbers of ferns adapted to semi-desert or otherwise exposed conditions in the Southwest and Mexico have long perplexed taxonomists and biologists interested in the phylogenetic relationships and processes of evolution in these plants. With new biotechnological tools of molecular analysis, Drs. Gerald Gastony and George Yatskievych of Indiana University are studying genetic variation in chloroplast DNA of representative samples of genera and species of Cheilanthoid ferns of North America, to solve this problem. Because DNA is not subject to modifying environmental influences in the way that stems, leaves, and reproductive structures are, the comparison of nucleotide differences among species can reveal genealogical affinities of the species examined. By digesting the chloroplast DNA with enzymes that cleave the molecule at specific nucleotide sites (so-called restriction-site enzymes, developed from bacteria) comparative data from a large number of species can be obtained. Their preliminary data reveal extensive amounts of restriction-enzyme site variability, indicating extensive mutational differences among species. Computer programs will be used to analyze the data and to arrange species into the most probable evolutionary groupings on the basis of their shared DNA characteristics. This phylogeny will then permit detailed analysis of processes of speciation and of character convergence in these ferns in their adaptive evolution to harsh habitats.