Molecular Advances in Severe Acute Respiratory Syndrome-associated Coronavirus (SARS-CoV)

Chow, Ken Yan Ching; Hon, Chung Chau; Hui, Raymond Kin Hi; Wong, Raymond Tsz Yeung; Yip, Chi Wai; Zeng, Fanya; Leung, Frederick Chi Ching

The phylogenetic relationship by the comparison of the deduced amino acid sequences of the replicase gene and four structural genes (S, E, M, N) with other coronaviruses was described (12 -14 ) . The conclusions drawn by the different research groups were similar, with the observation that SARS-CoV itself forms a distinct cluster-the fourth group of Coronaviridae, a notion supported by the high bootstrap values (above 90%). As a result, it has been concluded that the SARS-CoV is phylogenetically equidistant from all other known coronaviruses. Moreover, no detectable recombination event was concluded in the similarity plot on the whole genome alignment with other coronaviruses (14 ) . The above findings suggest that the SARS-CoV is neither a mutant nor a recombinant of existing coronaviruses, and that the possibility of such a virus emerging as a product of genetic engineering can be excluded, as it is unlikely to generate an infectious coronavirus with 50% of its genome different from the existing coronaviruses (9 ) .