PRF/J: A Molecular Systematic Study of Chromosomal, Phytochemical, and Morphological Evolution in Calycadenia (Asteraceae)

建议对加州特有的一年生花冠属内的表型进化进行分子研究。这些约12个种和30个小种或变型的染色体、类黄酮和形态进化的不寻常和良好分辨的模式使Calycadenia成为研究具有广泛系统意义的问题的模式系统。综合的叶绿体DNA和核DNA限制酶切点多态性分析被建议用来确定这些分类群的进化分化的模式和相对时间以及伴随的表型特征。这项研究涉及的问题包括：(1)选择在染色体进化中的作用，(2)进化分歧和染色体配对之间的关系，(3)复杂解剖特征中进化平行的程度，(4)两个高度独特的单型属(紫薇属和盲瓣属)及其伴生的一套独特表型特征的可能起源。以及(5)建议濒危物种--弗雷蒙蒂亚种的分类有效性。这项研究将是第一次将来自细胞遗传学、植物化学和形态学的大量系统发育信息数据与叶绿体和核DNA中不同核苷酸序列的进化数据相结合。初步的叶绿体DNA限制酶切位点数据显示，在这一群体中进行分子系统发育分析的种间变异水平是理想的。//

Molecular studies of phenotypic evolution within the Californian-endemic, annual genus Calycadenia are proposed. Unusual and well-resolved patterns of chromosomal, flavonoid, and morphological evolution among these ca. 12 species and 30 races or forms make Calycadenia a model system for examining questions of broad systematic significance. Integrated chloropast DNA and nuclear DNA restriction site polymorphism analyses are proposed to determine patterns and relative timing of evolutionary divergence of these taxa and accompanying phenotypic characters. Issues addressed by this study would include (1) the role of selection in chromosome evolution, (2) the relationship between evolutionary divergence and chromosome pairing, (3) the extent of evolutionary parallelism in complex anatomical features, (4) the possible origin from within Calycadenia of two highly-distinctive monotypic genera (Osmadenia and Blepharipappus) and their accompanying suites of unique phenotypic characters, and (5) the taxinomic validity of a proposed-endangered species, C.fremontii. This study would be among the first to integrate extensive phylogenetically-informative data from cytogenetics, phytochemistry, and morphology with evolutionary data from diverse nucleotide sequences in both chloroplast and nuclear DNA. Preliminary chloroplast DNA restriction site data revealed an ideal level of interspecific variation for conducting molecular phylogenetic analysis in this group. //