Localization of Nucleolar Organizer Regions (NORs) of 4 Gibbon Species in Thailand by Ag-NOR Banding Technique

Abstract

Summary Localization of nucleolar organizer regions (NORs) of four gibbon species in Thailand was studied. Blood samples were taken from 1 male each of the following 3 species: white-handed gibbon (Hylobates lar), pileated gibbon (H. pileatus), and white-cheeked gibbon (Nomascus leucogenys): and 1 female of the dark-handed gibbon (H. agilis). These were subjected to standard whole blood T-lymphocyte culture. The samples were harvested by colchicine-hypotonic-fixation-air-drying technique and were followed by the Ag-NOR banding technique. The results showed that the H. lar had NORs on chromosome pair 13 (submetacentric chromosomes) while the H. agilis had NORs on chromosome pair 10 (submetacentric chromosomes) and H. pileatus had NORs on chromosome pair 15 (metacentric chromosomes). In addition, the N. leucogenys showed 5 positions with NORs on chromosomes pairs 23, 24 (acrocentric chromosomes) and the Y-chromosome (submetacentric chromosome). These results are useful to confirm marker chromosomes of gibbons and also comprise basic genetic information for these animals. Kew words Gibbon, Karyotype, Chromosome, Idiogram, Ag-NOR banding. Thailand is tropical country thus its weather and surrounding are suitable for organism that causes high diversity. Wild animals are one element that show the diversity and also important in ecology and food chain. The destruction of forest causes wild animal extinction or risk of extinction includes animal in family Hylobatidae. There were 13 families, 60 genera and 232 species of animals in order Primate (Wilson and Cole 2000); however, only 3 families, 5 genera, and 13 species were found in Thailand. Thai gibbon species consists of 4 species, white-handed gibbon (Hylobates lar Linnaeus 1771), agile gibbon or dark-handed gibbon (Hylobates agilis Cuvier 1821), pileated gibbon (Hylobates pileatus Gray 1842), and white-cheeked gibbon (Nomascus leucogenys Ogilby 1840) (Lekagul and McNeely 1988, Giessmann 1995) (Fig. 1). These species are listed as protected species in Wild Animal Reservation and Protection Act (1992), and in the International Union for the Conservation of Nature (IUCN) as vulnerable species. The Convention on International Trade in Endangered Species (CITES) of wild fauna and flora also listed these species in Appendix I (Brokelman 1981).