The Classification of Prokaryotes

9306171 Woese在新的细菌研究中，伊利诺伊大学的Carl Woese博士通过分析核糖体RNA的基因组序列数据，继续研究微生物的进化、系统发育和分类，以量化细菌群之间的遗传差异。通过比较来自各种生物体的核糖体RNA序列，可以使用计算机分析所涉及的数百和数千个核苷酸碱基来构建谱系亲和的分支模式。类群之间的核苷酸差异很少表明进化关系密切（共享来自接近的共同祖先的相似基因组），而较大的突变差异表明谱系之间更古老的分歧。这次研究的目标有三个群体：紫色光合细菌；某些被忽视的革兰氏阳性菌群；还有噬细胞亚群，弹性细菌亚群和拟杆菌亚群。细菌系统发育分析的另一个好处是能够设计诊断分子“指纹”探针，可用于生态学和医学研究，以识别未知细菌。此外，通过比较核苷酸序列分析揭示的系统发育关系为研究微生物生理学、生物化学和生态学的其他方面提供了一个进化框架。

9306171 Woese In renewed studies on bacteria, Dr. Carl Woese of University of Illinois continues investigations of the evolution, phylogeny, and classification of microbes through the analysis of genomic sequence data from ribosomal RNA in order to quantify genetic differences between groups of bacteria. By comparing the sequence of ribosomal RNA from a variety of organisms, a branching pattern of genealogical affinity can be constructed with the use of computer analyses of the hundreds and thousands of nucleotide bases involved. Few nucleotide differences between taxa indicate close evolutionary relationship (the sharing of similar genomes from a close common ancestor) whereas greater mutational differences indicate more ancient divergence between lineages. Three groups are targeted for study this time: purple photosynthetic bacteria; certain neglected groups of Gram positive bacteria; and cytophaga, flexibacter, and bacteroides subgroups. %%% An additional benefit of the phylogenetic analysis of bacteria is the ability to design diagnostic molecular "fingerprinting" probes, that can be used in ecological and medical studies to identify unknown bacteria. Also, the phylogenetic relationships revealed through comparative nucleotide sequence analyses provide an evolutionary framework for studying other aspects of microbial physiology, biochemistry, and ecology.