The Identification of Sex-Chromosomes and Karyological Analysis of Rice Frog, <i>Fejervarya limnocharis</i>(Anura, Ranidae) from Northeast Thailand

Abstract

Summary Karyological analysis of the rice frog (Fejervarya limnocharis) from Northeast Thailand was conducted. Frog chromosome preparations were obtained by the squash technique from bone marrow and testis. Conventional staining and Ag-NOR banding techniques were applied to stain the chromosome with Giemsa s solution. The results showed that the number of diploid chromosome is 2n = 26, while the fundamental number (NF) is 52 in both males and females. The types of autosome were 4 large metacentric, 6 large submetacentric, 8 small metacentric, 4 small submetacentric and 2 small acrocentric chromosomes. The present study also revealed that the sex chromosome system of F. limnocharis was XY, in which the X and Y were classified as small metacentric and small submetacentric chromosomes, respectively. Nucleolar organizer regions (NORs) are located at the secondary constriction of the short arm near the centromere in submetacentric chromosome pair 6. We found that during metaphase I the homologous chromosomes showed synapsis, which can be defined as the 13 ring bivalents and 13 haploid chromosomes at metaphase II as diploid species. The karyotype formula is as follows: 2n (26) = L 4 m +L 6 sm +S 8 m +S 4 sm +S a 2 +sex-chromosomes (XY)

Cytogenetic Study of Three Microhylid Species (Anura, Microhylidae) from Thailand

“…Cytological evidence that was supportive of male heterogamety (XX/XY sex chromosome) has been published by Iturra and Veloso (1981) and Schmid 1981), as well as Eupsophus insularis (Cuevas and Formas 1996), R. tagoi and R. sakuraii from Tokyo (Ryuzaki et al 1999). Additionally, the XX/XY sex chromosome system was found in the genus Bufo (Siripiyasing et al 2008) and also in rice frogs, Fejervarya limnocharis (Patawang et al 2014). The existence of the highly differentiated XX/XY sex chromosome has been reported in Gastrotheca riobambae by Schmid et al (1983), in G. ovifera and G. walkeri by Schmid et al (1988), in G. pseustes by Schmid et al (1990), and in Eleutherodactylus maussi by Schmid et al (1992).…”

Cytotoxic evaluation of rice field frogs (Fejervarya limnocharis) from gold mine area with arsenic contamination

“…The F. limnocharis samples displayed a terminal Ag-NOR on chromosome pair 6. In addition, Patawang et al [24] reported that Ag-NOR was located on a region adjacent to the centromere of chromosome pair 6. This data describes basic knowledge of F. Nucleus limnocharis, and its cytogenetics will be applied to studies on breeding, conservation and chromosomal evolution in this frog.…”