The First Report on Standardized Karyotype and Idiogram of Indochinese Silvered Langur, Trachypithecus germaini germaini (Primates, Colobinae) in Thailand

The first standardized karyotype and idiogram of Indochinese silvered langur (Trachypithecus germaini germaini) in Thailand was established in the present study. Blood samples were taken from two males and two females then subjected to standard whole blood T-lymphocyte culture. The samples were harvested by colchicine-hypotonic-fixation-air-drying technique and followed by conventional staining, GTG-banding and high-resolution techniques with Giemsa's. The results revealed that its diploid number was 2n=44 and fundamental number (NF) was 88 in both males and females. The autosomes comprise 6 large metacentric, 10 large submetacentric, 2 large acrocentric, 6 medium metacentric, 14 medium submetacentric, 2 small submetacentric, and 2 small acrocentric chromosomes. We found that nucleolar organizer regions (the representative of chromosome marker) are located on the long arms near centromeres of a pair submetacentric autosome 17. The X chromosome was a largest submetacentric chromosome while the Y chromosome was the medium submetacentric chromosome. The GTG-banding and high-resolution techniques demonstrated that the respective numbers of bands and locations in T. germaini germaini were 245 and 301 respectively. Each homologous chromosome pair appears clearly differentiated. The karyotype formula for T. germaini germaini could be deduced as: 2n (44)=L6m+L10sm+L2a+M6m+M14sm+S2sm+S2a+sex-chromosomes.