CHLOROPLAST DNA EVOLUTION AND ADAPTIVE RADIATION IN THE HAWAIIAN SILVERSWORD ALLIANCE (ASTERACEAE MADIINAE)
CHLOROPLAST DNA EVOLUTION AND ADAPTIVE RADIATION IN THE HAWAIIAN SILVERSWORD ALLIANCE (ASTERACEAE MADIINAE)
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DOI：
10.2307/2399629
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发表时间：
1990-01-01
影响因子：
1.9
通讯作者：
DVORAK, J
中科院分区：
文献类型：
--
作者：
BALDWIN, BG;KYHOS, DW;DVORAK, J
叶绿体DNA（cpDNA）的限制性位点的变化之间的24个现存的27种夏威夷银剑联盟（Argyroxiphium，Dubautia，Wilkesia）进行了研究，以加强了解系统发育模式和进化过程中，这个突出的例子岛屿适应性辐射。16个限制性内切酶分析显示，共有55个限制性位点的差异，36个被共享的一个子集，至少两个类群。在这些类群之间的成对比较，cpDNA分歧范围从0到0.46%的核苷酸。叶绿体DNA分歧内Dubautia超过了所有属间比较。一个严格的共识树从王格简约分析这种变化是拓扑一致的进化决议从Dollo简约和Fitch Margoliash遗传距离算法。这些结果和表型分析结果之间的冲突表明，这些分类群之间没有cpDNA分子钟。cpDNA的一致同源性表明银剑联盟的单系生殖，与生物系统学和细胞遗传学证据的雅阁一致。这些数据进一步表明：（1）在银剑联盟的历史早期，谱系的快速辐射;（2）很少有成功的导致新物种谱系的北半球迁移;（3）在n = 13的Dubautia组内，单向的，由老到年轻的岛屿迁移模式;（4）Wilkesia和五个考爱岛Dubautia物种之间的形态和cpDNA进化的相对速率之间的显著不一致;（5）某些银剑草属（Argyroxiphium）和杜氏草属（Dubautia）类群间的杂交物种形成或广泛渐渗。这些系统发育的结论需要测试与核DNA的分子分析，以澄清杂交的程度影响了这一生殖和遗传凝聚力的植物群的进化。
Chloroplast DNA (cpDNA) restriction site variation among 24 of 27 extant species of the Hawaiian silversword alliance (Argyroxiphium, Dubautia, Wilkesia) was studied to enhance understanding of phylogenetic pattterns and evolutionary processes in this outstanding example of insular adaptive radiation. Analysis with 16 restriction endonucleases revealed a total of 55 restriction site differences, 36 being shared by a subset of at least two taxa. In pairwise comparisons among these taxa, cpDNA divergence ranged from 0 to 0.46% of nucleotides. Chloroplast DNA divergence within Dubautia exceeded that of all intergeneric comparisons. A strict consensus tree from Wanger parsimony analyses of this variation was topologically congruent with evolutionary resolutions from Dollo parsimony and the Fitch-Margoliash genetic distance algorithm. Conflict between these outcomes and results from a phenetic analysis suggest a cpDNA molecular clock is not operating among these taxa. The cpDNA consensus phylogeny indicates monophylesis of the silversword alliance, in accord with biosystematic and cytogenetic evidence. These data further suggest: (1) rapid radiation of lineages early in the history of the silversword alliance; (2) few successful interisland migrations that led to new species lineages; (3) a unidirectional, older-to-younger island pattern of migration within the n = 13 Dubautia group; (4) striking inconsistency between relative rates of morphological and cpDNA evolution among Wilkesia and five Kauaian Dubautia species; and (5) hybrid speciation or extensive introgression among certain Argyroxiphium and Dubautia taxa. These phylogenetic conclusions require testing with molecular analyses of nuclear DNA to clarify the extent to which hybridization has influenced the evolution of this reproductively and genetically cohesive group of plants.