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

在加州特有的，一年生属Calycadenia提出表型进化的分子研究。在这些大约12个种和30个种或形式中，不寻常的和很好解决的染色体、类黄酮和形态进化模式使Calycadenia成为研究广泛系统意义问题的模式系统。结合叶绿体DNA和细胞核DNA限制性内切位点多态性分析来确定这些分类群进化分化的模式和相对时间以及相关的表型特征。本研究解决的问题将包括：(1)选择在染色体进化中的作用；(2)进化分歧与染色体配对之间的关系；(3)复杂解剖特征的进化平行程度；(4)两个高度独特的单型属（Osmadenia和Blepharipappus）在Calycadenia内的可能起源及其伴随的独特表型性状；(5)一种疑似濒危物种C.fremontii的分类学有效性。这项研究将是第一个将来自细胞遗传学、植物化学和形态学的广泛系统发育信息数据与来自叶绿体和核DNA中不同核苷酸序列的进化数据整合在一起的研究。初步的叶绿体DNA限制性内切位点数据显示，在这一群体中进行分子系统发育分析具有理想的种间变异水平。//

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. //