Molecular phylogeny of Juglans (Juglandaceae):: a biogeographic perspective
Molecular phylogeny of Juglans (Juglandaceae):: a biogeographic perspective
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DOI：
10.1007/s11295-006-0078-5
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发表时间：
2007-10-01
影响因子：
2.4
通讯作者：
Simon, Charles J.
中科院分区：
文献类型：
--
作者：
Aradhya, Mallikarjuna K.;Potter, Daniel;Simon, Charles J.
东亚和北美东部的分离核桃提供了一个机会，估计时间，因为欧亚和美洲血统的分歧，并将其与古植物学证据进行比较。利用5个叶绿体DNA非编码间隔区（NCS）序列：trnT-trnF、psbA-trnH、atpB-rbcL、trnV-16 S rRNA和trnS-trnfM以及早期研究的数据（matK、ITS和核RFLP）重建了主要谱系的分化发生并估计了主要谱系的分化时间。包括核桃属4个组的17个分类群和2个外类群，枫杨和薄壳山核桃。NCS数据仅与matK数据一致。这两个最大简约（MP）和最大似然（ML）的分支图是一致的，在截面水平，并揭示了三个支持单系分支对应的部分核桃，核，Rhysocaryon在NCS和合并分析。唯一现存的美国胡桃，核桃灰被放置在解决不好，但良好的支持Rhysocaryon。在NCS和合并分析之间，Rhysocaryon和Atracyon内的分类群的位置不一致。总体而言，研究结果表明：（1）核桃组内部和组间的NCS序列差异很小，matK数据的加入仅略微提高了Rhysocaryon内部的分辨率;（2）在NCS和组合数据的MP和ML分析中，Juglans组的早期差异暗示了其古老的起源，而化石证据表明Rhysocaryon组和Acutocaryon组的最早差异;（3）现存的分类群可能不具备揭示该属进化历史的足迹。
The eastern Asian and eastem North American disjunction in Juglans offers an opportunity to estimate the time since divergence of the Eurasian and American lineages and to compare it with paleobotanical evidence. Five chloroplast DNA noncoding spacer (NCS) sequences: trnT-trnF, psbA-trnH, atpB-rbcL, trnV-16S rRNA, and trnS-trnfM and data from earlier studies (matK, ITS, and nuclear RFLP) were used to reconstruct phylogeny and to estimate the divergence time of major lineages. Seventeen taxa from four sections of Juglans and two outgroup taxa, Pterocarya stenoptera and Carya illinoiensis were included. NCS data was congruent only with matK data. Both maximum parsimony (MP) and maximum likelihood (ML) cladograms were concordant at the sectional level and revealed three well-supported monophyletic clades corresponding to sections Juglans, Cardiocaryon, and Rhysocaryon in both NCS and combined analyses. The single extant American butternut, Juglans cinerea was placed within the poorly resolved, but well-supported Rhysocaryon. Placement of taxa within Rhysocaryon and Cardiocaryon were inconsistent between NCS and combined analyses. Overall, the results suggest that: (1) the NCS sequence divergence observed within and between sections of Juglans is low and the addition of matK data only marginally improved resolution within Rhysocaryon; (2) the early divergence of section Juglans in both MP and ML analyses of NCS and combined data implies its ancient origin in contrast to fossil evidence, which suggests the earliest divergence of sections Rhysocaryon and Cardiocaryon; and (3) the extant taxa may not hold the footprints to unravel the evolutionary history of the genus.