| 山羊草属异源多倍体物种核rDNA ITS区的进化 |
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| 引用本文： | 王超,王建波,施苏华,钟扬.山羊草属异源多倍体物种核rDNA ITS区的进化[J].中国科学院研究生院学报,2000,38(3):211-217. |
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| 作者姓名： | 王超 王建波 施苏华 钟扬 |
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| 摘 要： | 本文测定了山羊草属Aegilops 3个组中异源多倍体物种的核rDNA ITS区序列，并用邻接法进行了聚类分析。结果表明，多倍体物种的ITS区序列长度为559∽606bp，其中ITS1、ITS2分别有变异位点51、42个，且存在多态位点。多倍体种均与各自的某一祖先种构成稳定分支，说明在杂交-多倍化后，这些多倍体的ITS区在同步进化的作用下已向着其某一祖先种的ITS区进化。对于sect．Vertebrata的异源多倍体物种来说，其ITS区主要向其祖先种Ae．umbellulata(UU)的ITS区进化，这与山羊草属的细胞遗传学研究结果基本一致。在sect．Cylindropyrum和sect．Polyeides中，Ae．cylindrica(CCDD)朝着Ae．caudata (CC)进化；Ae．ventricosa(DDMvMv)朝着Ae．comosa(MM)进化；Ae．vavilovii(DDMMSS)朝着Ae．crassa (DDMM)进化。
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| 关 键 词： | 山羊草属 异源多倍体 ITS区序列 进化 |
Evolution of Internal Transcribed Spacer Region of Nuclear Ribosomal DNA in Allopolyploids of Aegilops |
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| WANG Chao,WANG Jian-Bo,SHI Su-Hua,ZHONG Yang.Evolution of Internal Transcribed Spacer Region of Nuclear Ribosomal DNA in Allopolyploids of Aegilops[J].Journal of the Graduate School of the Chinese Academy of Sciences,2000,38(3):211-217. |
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| Authors: | WANG Chao WANG Jian-Bo SHI Su-Hua ZHONG Yang |
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| Abstract: | Hybridization with subsequent polyploidy is a prominent process in evolution of higher
plants, but few data address the evolution of homeologous sequences after polyploidy. The internal
transcribed spacer (ITS) of nuclear ribosomal DNA (nrDNA) from eleven allopolyploid species in
Aegilops was investigated by PCR amplification and direct sequencing. The sequences obtained were
used to study the evolution of ITS region in allopolyploid species. The length of ITS region varied
from 599 to 606 bp and the number of variable sites was 93, i.e. 51 and 42 for ITS1 and ITS2 re-
spectively. Some polymorphic sites were observed in polyploid species, and this indicated that the
ancestral sequences had not been homogenized completely by concerted evolution. Distance matrix
analysis of diploid and polyploid species by neighbor-joining method, using Triticum monococcum as
outgroup, resulted in well-resolved neighbor-joining tree indicating that the ITS regions of UUMM
and UUSS genome ( sect. Vertebrata) were homogenizing toward those of UU ancestal genome. This
result is in agreement with the results of ctyogenetics of Aegilops. On the other hand, the neighbor-
joining tree including the D-genome group species (sect. Cylindropyrum and sect. Polyeides ) com-
prised three clades (CC-DDCC, UU-DDMM-DDMMSS-DDMMUU and MM-DDMvMv), which sug-
gested that concerted evolution was homogenizing the ITS region of the polyploid derivatives to either of their ancestors. |
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| Keywords: | Aegilops Allopolyploid ITS sequence Evolution |
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