Prion diseases which are a group of fatal neurodegenerative disorders affect both animals and humans. It is believed that the prions are infectious agents responsible for transmissible spongiform encephalopathies. The present study was performed to concentrate on the molecular and phylogenetic analysis of prion coding region in one-humped camels rearing in Iran. In order to assess the genetic relatedness of dromedary camels studied in Iran the nucleotide and deduced amino acid sequences of the prion region were compared with some corresponding sequences of earlier described mammalians. The nucleotide sequence comparison indicated that eight dromedary camels of Iran share approximately 100% similarity among themselves. Phylogenetic clustering in the prion coding region of all mammalians included in the analysis was distinctly divided into three lineages in which Iran-dromedary camel clustered with two species Sus scrofa and Equus asinus. Data analysis demonstrated that dromedary camel 2 from Germany contains one amino acid deletion in comparison to other camels. The codon (TGA) at position 564-566 has been deleted, leading to deletion of amino acid methionine at position 189. In comparison to other mammalians, all camels possessed an amino acid deletion at position 71 of amino acid sequence; the amino acid Gly has been deleted from this position. The existence of such genetic variations must be taken into consideration, if they are found to be related to the host resistance against the prion disease.

ABSTRACT