A Novel Robertsonian Translocation [57,rob(1/29)(4/28)] and Polymorphism of Nucleolar Organizer Regions (NORs) of Captive Thai Banteng (Bos javanicus birmanicus)

Abstract

Robertsonian translocation (centric fusion) has been well documented in domestic cattle, with the most commonly occurring fusion involving chromosomes 1 and 29. Fifty conventional staining, G-banding, C-banding and NOR-banding metaphase spreads derived from lymphocyte cultures were analyzed for each animal. The Thai banteng has diploid chromosome number of 2n=57 in males and females instead of the normal 2n=60. The chromosomes presence of an extra acrocentric chromosome and 2 submetacentric chromosome while the loss of 6 telocentric chromosomes was observed [57, rob(1/29)(4/28)]. Results from G-banding analysis confirm that 6 autosomes involved in the translocation are bovine homologues 1/29 and 4/28. This is the first report on polymorphism of nucleolar organizer regions (NORs) of Thai banteng. It indicated the presence of heteromorphism of telocentric chromosomes in both male and female, there are NORs in 1 telocentric chromosome but it dose not exist in another telocentric chromosome.