Isolation and characterization of sixty sequences of cot-1 DNA from the Asiatic black bear, Ursus thibetanus

Abstract

The Asiatic black bear (Ursus thibetanus) is a class II protected species in China whose genome is not well characterized. All mammalian genomes have a high proportion of repetitive sequences; thus, studying the repetitive sequences of the Asiatic black bear can provide new insight into the organization of its genome. It is well known that cot-1 DNA is enriched for repetitive DNA elements with high and moderately high copy numbers within the genome. In this small-scale study, cot-1 DNA from U. thibetanus was first isolated and characterized using DNA reassociation kinetics, then a Southern blotting probe was used to indicate the presence of polymorphic repetitive DNA families in this species. Analysis of homologous sequences by online database searches revealed that the obtained fragments contained satellite sequences, mitochondrial DNA, retrotransposons, DNA transposons, and unclassified fragments whose deduced amino acid sequences has significant relationships to known proteins. The data produced by this study may lead to more research into repetitive DNAs.

Key words: Asiatic black bear, cot-1 DNA, repetitive elements, southern blotting