Abstract. Donbundit N, Bausriyod P, Tanomtong A, Srisamoot N, Sumontha M, Thongnetr W, Patawang I, Supiwong W, Ditcharoen S, Muanglen N, Kaewmad P. 2022. Karyomorphological delineation, and the NOR loci on the sex chromosome in three species of Chrysopeleinid (Chrysopeleinae: Colubridae) from Thailand. Biodiversitas 23: 3813-3819. The description of chromosomal characteristics of three snakes from Thailand namely, Ahaetulla fusca, A. prasina, and Chrysopelea ornata was by using conventional staining and Ag-NOR banding techniques. The results showed that the same diploid chromosome number (2n) = 36 (16 macrochromosomes + 20 microchromosomes) and the fundamental number (NF) was 54 while the karyotype formulae in these three species are as follows: A. fusca; 2n(36) = Lm6 + Sm2+ Ssm4 + Sa2+ ZZ/ZW + 20 microchromosomes, A. prasina; 2n(36) = Lm6+ Sm6+ Sa2+ ZZ/ZW + 20 microchromosomes and C. ornata; 2n(36) = Lm4+ Lsm2+ Sm2 + Ssm4+ Sa2+ ZZ/ZW + 20 microchromosomes. Besides, the ZZ/ZW sex chromosome was observed in all species, whereas C. ornata was discovered the heteromorphic sex chromosome for the first time. Nucleolar organizer regions (NORs) are located on telomeric region of one pair in all species, while located on microchromosomes in A. fusca and A. prasina, whereas C. ornata was detected on sex chromosomes. Therefore, the Z chromosome revealed the NOR on the telomeric region of the long arm, while NOR of the W chromosome was located on the telomeric region of the short arm.

Abstract. Mingkwan B, Sassi FDMC, Muanglenm N, Pinmongkhonkul S, Pinthong K, Tongnunui S, Yeesin P, Tanomtong A, Liehr T, Cioffi MDB, Supiwong W. 2023. Evolutionary tracks of chromosomal diversification in Trichopsis (Anabantiformes, Osphronemidae) fishes: New insights from a molecular cytogenetic perspective. Biodiversitas 24: 1551-1559. This study investigated the chromosomes of three Trichopsisspecies (namely Trichopsis pumila, Trichopsis vittata, and Trichopsis schalleri) using conventional (Giemsa stain, Ag-NOR) and molecularcytogenetic techniques. Fluorescence in situ hybridization (FISH) with repetitive DNAs, including 5S and 18S rDNAs, and microsatellites as probes were also performed. Our results indicated a conserved diploid number of 46 (2n) for all analyzed species of both sexes, although varying in their karyotype structure. Furthermore, T. schalleri and T. vittata karyotypes were presented with only acrocentric chromosomes (46a), while T. pumila had a submetacentric pair in addition to acrocentric ones (2sm+44a). Positive Ag-NOR sites were differentially found in each species adjacent to the acrocentric chromosome's centromeric and/or interstitial sub-centromeric regions. Both 5S and 18S rDNAs vary between the analyzed species, but all were localized in multiple sites. However, the distribution pattern of microsatellites differed in each species, mostly scattering at peri-centromeric and telomeric regions. These findings show that Trichopsis species, while having a conserved diploid number, differ significantly in the distribution of repetitive sequences in their karyotypes, particularly for rDNAs. These species-specific patterns can be useful for characterizing and identifying further different species and examining the evolutionary mechanisms that drove the evolution of these fishes' karyotypes.