Hybrid origins of Ixeris nakazonei (Asteraceae, Lactuceae) in the Ryukyu Archipelago, Japan:: evidence from molecular data
Hybrid origins of Ixeris nakazonei (Asteraceae, Lactuceae) in the Ryukyu Archipelago, Japan:: evidence from molecular data
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DOI：
10.1046/j.1095-8339.2003.00143.x
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发表时间：
2003-03-01
影响因子：
2.4
通讯作者：
Yokota, M
中科院分区：
文献类型：
--
作者：
Denda, T;Yokota, M
利用核DNA（nDNA）和叶绿体DNA（cpDNA）分子标记对采自琉球群岛（冲绳岛）和日本中部厚见半岛（小石滨）的中华苦碟子（Ixerisnakazonei）的杂种起源进行了研究。结果表明，大部分四倍体中山红（2n = 32）的nDNA都来自于两个亲本：弱花苜蓿（2n = 48）和匍匐苜蓿（2n = 16）。考虑到染色体数目的中间性，第一个四倍体的Lnakazonei应该是由Ldebilis和Lrepens种间杂交直接产生的。冲绳四倍体中所有的四倍体都含有匍匐乳杆菌的cpDNA，而厚见半岛的四倍体中含有弱乳杆菌的cpDNA，表明四倍体至少有两个独立的起源。另一方面，所有六倍体的Lnakazonei（2n = 48），有Ldebilis的cpDNA，但一些六倍体的nDNA的推定父母。柔弱苦碟子和匍匐苦碟子也可能参与了六倍体的起源，尽管这种细胞型的建立过程仍然不清楚。由于六倍体中带百合与弱百合在细胞学上无明显区别，因此可以与弱百合回交。在冲绳岛可能发生了由中带百合介导的二倍体白三叶向六倍体弱花百合的渐渗。(C)2003林奈学会伦敦，林奈学会植物学杂志，2003，141，379387。
The proposed hybrid origin of Ixeris nakazonei collected in the Ryukyu Archipelago (Okinawajima) and the Atsumi Peninsula (Koijigahama) of central Japan was examined using nuclear DNA (nDNA) and chloroplast DNA (cpDNA) markers. The results indicated that most tetraploids of L nakazonei (2n = 32) had nDNA of both putative parents, L debilis (2n = 48) and L repens (2n = 16). The first tetraploid of L nakazonei must have arisen directly from interspecific hybridization between L debilis and L repens, considering the intermediacy of the chromosome number. All tetraploids on Okinawajima had cpDNA of L repens, while those in the Atsumi Peninsula had cpDNA of L debilis, indicating that the tetraploid has at least two independent origins. All hexaploids of L nakazonei (2n = 48), on the other hand, had cpDNA of L debilis, but some of the hexaploids had nDNA of both putative parents. Ixeris debilis and L repens may also be involved in the origin of the hexaploid, although the establishment process of this cytotype is still obscure. Since the hexaploid of L nakazonei is cytologically indistinguishable from L debilis, it can backcross with L debilis. Introgression from diploid L repens to hexaploid L debilis mediated by L nakazonei possibly occurs on Okinawajima. (C) 2003 The Linnean Society of London, Botanical Journal of the Linnean Society, 2003, 141, 379387.