A CYTOGENETIC STUDY ON THREE SPECIES OF TURTLE

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.