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TitleDNA comparisons of the two orthopoxviruses monkeypox and variola
AuthorPare, Nicola Jennifer
TypeMSc (Med)
AbstractAlthough smallpox has been eradicated there are animal poxviruses which are closely related. It is desirable to measure the closeness of this relation to assess whether Variola virus could re-emerge as a complex mutant of an animal poxvirus. The most likely candidate is Monkeypox, which can produce human infection clinically resembling smallpox. The work in this thesis is the beginning of a detailed comparison of the DNA of Variola and Monkeypox. A 15.3kb section of the Variola genome was compared with a corresponding 14.4kb region of Monkeypox. This enabled both a comparison of corresponding sequences and the location of a short sequence present only in variola. Initially restriction enzyme mapping of the two stretches of DNA showed considerable homology and narrowed down the area containing any nonhomologous Variola sequences to within 2.9kb. Sequence comparisons show a level of 96% similarity. When the 2.9kb Variola fragment was compared with the corresponding 2.4kb Monkeypox fragment, a 400bp insert was found in Variola flanked by sequences common to both viruses. Analysis of the insert revealed two overlapping open reading frames present on opposite DNA strands. The DNA and putative polypeptide sequences were compared with known sequences, but no significant homology was detected. The presence or absence of this sequence in other orthopoxviruses is being established, but the expression of these open reading frames in vivo and function of the putative polypeptides is still to be investigated.
PublisherUniversity of Cape Town
PublisherFaculty of Health Sciences
PublisherDivision of Medical Biochemistry&Structural Biology