First Cytogenetic Study of Malayan Snail-eating Turtle, Malayemys macrocephala (Testudines, Geoemydidae) in Thailand

抄録

The first cytogenetics of the Malayan snail-eating turtle (Malayemys macrocephala) from the Chi river basin, Khon Kaen Province, Thailand, were studied. Blood samples were taken from two male and two female turtles. Standard T-lymphocyte cell culture at 26°C for 96 h was applied. The mitotic chromosomes were harvested by colchicine-hypotonic-fixation-air drying technique. Conventional staining and GTG-banding techniques were applied to stain the chromosomes with 20% Giemsa's solution. Results showed that the number of diploid chromosomes was 2n=50, while the fundamental number (NF) was 40 in both males and females. The types of macrochromosomes were 4 metacentric, 8 submetacentric, 6 acrocentric, 4 telocentric chromosomes, and 28 microchromosomes. The GTG-banding technique showed that each chromosome pairs could be clearly differentiated and the numbers of bands in the M. macrocephala was 99. There is no observation of strangely size chromosomes related to sex. The karyotype formula is as follows:
2n (50)=L₂^m+L₂^sm+M₂^a+S₂^m+S₆^sm+S₄^a+S₄^t+28 microchromosomes