核型解析によるイチョウ雌雄間の染色体の違いと fluorescence in situ hybridization (FISH) による染色体上のrDNAマッピング Chromosomal Difference between Male and Female Trees of Ginkgo biloba Examined by Karyotype Analysis and Mapping of rDNA on the Chromosomes by Fluorescence in situ Hybridization

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Abstract

イチョウは雌雄異株であるが, 現在, 雌雄の判別は生殖器官の観察によるしかない.そこで, 染色体における雌雄の違いについて調査した.染色体数は雌雄ともに24本(12対)であった.付随体を持つ染色体の数は, 雄株と雌株それぞれ3本と4本であった.これら付随体の2本はもっとも大きな中部動原体型染色体の短腕にあり, その他の雄株の1本と雌株の2本は次中部動原体型染色体の長腕にあった.CMA染色の結果, 雌雄ともに2本のもっとも大きな中部動原体型染色体の短腕と2本の次中部動原体型染色体の長腕のそれぞれの二次狭窄部に, 合計4か所の黄色いバンドが認められた.5S rDNAと26S-5.8S-18S rDNAをプローブとしたFISH解析で両領域ともに二次狭窄部に位置し, 雌雄間に違いはなかった.また, これらの位置はCMAバンドと同様の場所に検出された.したがって, イチョウの雌雄性の判別は付随体の数によって判別できるが, 5S rDNAと26S-5.8S-18S rDNAをプローブとしたFISHシグナルやCMA染色では判別できないことが明らかとなった.

The male and female trees of Ginkgo biloba can only be distinguished by studying the morphology of reproductive organs. This study was undertaken to investigate the chromosomal differences between the sexes of this dioecious species. The somatic chromosome number of the male and female trees is 24(2n=24). The difference in the karyotype of the male and female trees was observed in the number of satellite chromosomes. There were three in the male and four in the female trees. The satellites were observed on the two largest metacentric chromosomes in both male and female trees, whereas only one sub-metacentric chromosome in the male and two submetacentric chromosomes in the female tree. Chromosomes stained with chromomycin A_3 (CMA), exhibited yellow bands near the terminal of the short arms of the two largest metacentric chromosomes and the long arms of two sub-metacentric chromosomes in the male as well as the female trees. Utilizing fluorescence in situ hybridization (FISH) analysis with rDNA as probe, the signals were observed at the same four positions in both the male and female trees. Hence, the discrimination of male and female trees at the chromosome level can only be made on the basis of the number of satellites.

Journal

  • Journal of the Japanese Society for Horticultural Science

    Journal of the Japanese Society for Horticultural Science 74(4), 275-280, 2005-07-15

    園藝學會

References:  21

Cited by:  1

Codes

  • NII Article ID (NAID)
    110001815992
  • NII NACSIS-CAT ID (NCID)
    AN00025257
  • Text Lang
    ENG
  • Article Type
    Journal Article
  • ISSN
    00137626
  • NDL Article ID
    7425181
  • NDL Source Classification
    ZR7(科学技術--農林水産--農産)
  • NDL Call No.
    Z18-172
  • Data Source
    CJP  CJPref  NDL  NII-ELS  IR  NDL-Digital 
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