摘要:
本文以外周血淋巴细胞为材料,首次报道马来闭壳龟和地龟的核型,G带,C带和Ag－NORs,以及平胸龟的G带和C带。发现平胸龟的核型与前人报道的有差异。研究结果表明:平胸龟2＝54(14M＋4ST＋ST＋28m),N.F＝72,7＋6＋14。A组No.6qper有一次缢痕.Ag－NOAs位于A组的No.7qter。其全部染色体的着丝粒区均显示阳性C带,并且A组的No.7整条异染色质化；马来闭壳龟Zn＝52(18M＋4ST＋6T＋24m),N.E＝74,9＋5＋12。Ag－NORs位于A组No.7qter.全部染色体的着丝粒区均有深染C带,C组的No.1整条异染色质化；地龟核型Zn＝52(16M＋4ST＋6T＋26m),N.F＝72,8＋5＋13,A组No.7pper有一次缢痕。Ag－NORs位于A组No.7qper,呈异态。全部染色体着丝粒区C带阳性,A组的No.1qter和No.2,7pqter呈现C带阳性.在三种龟的G带型中,仅马来闭壳龟A组No.8和B组No.2有时呈现同源染色体间异型,其余均可进行同源配对.本文还讨论了核型的演化机制。
关键词:
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龟类
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核型
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G带
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C带
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Ag－NORs
Abstract:
The conventional karyotypes,G-bands,C-bands and Ag-NORs of three species of turtles have been studied. Platysternon megacephalum Gray has 2n =54(14M+4ST+8T+28m),N. F.=72,7+6+14(Karyotypic formula). The No.6 chromosome of group A has a secondary constriction (SC) in the q per. The Ag-NORs are on the No.7 q ter of group A; Cuora amboinensis (Daudin) has 2n=52(18M+4ST+ 6T+24m),N. F.=74,9+5+12. There are a pair of Ag-NORs in the No.7 q per of group A; Geoemyda spengleri Gmelin has 2n =52(16M+4ST+6T+26m),N.F.=72,8+5+13. The No.7 p per of group A has a SC. The Ag-NORs with hereromorphic phenomenon located on the No.7 q per of group A.All of the centromeric regions of the chromosomes showed staining of C-positihve for these three species. Besides this,the telomeric C-bands was found at the No.1 q ter of group A and the Nos.2,7 p q ter of group C in G. spengleri. The No.7 chromosome of group A of P. megacephalum and the No.1 chromosome of group C of C. amboinensis showed whole staining of C-positive.The chromosomes of G-banded were analyzed. The results show that each homologous pair has its own special G-banded patterns,so is possible to be paired in the karyotype.
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