Molecular Evolution of Group 2 Coronaviruses
Leen Vijgen, Els Keyaerts, and Marc Van Ranst
from: Coronaviruses: Molecular and Cellular Biology (Edited by: Volker Thiel). Caister Academic Press, U.K. (2007)
Coronaviruses are well-equipped to adapt rapidly to changing ecological niches based on two major forces that drive their viral evolution: mutation and recombination. Based on the available nucleotide and amino acid sequence information, the evolutionary relationships among coronaviruses can be inferred by using molecular phylogenetic approaches. The calculation of an evolutionary rate provides an indication of the rate at which mutations become fixed in the coronavirus population. The divergence of ancestral strains of existing coronaviruses with a different host-specificity can be dated back in history, thereby estimating the time in which potential interspecies transmission events occurred. A similar cross-species jumping led to the emergence of the SARS coronavirus, that has been proposed to be an early split-off from group 2 coronaviruses. Within group 2 a subdivision into murine hepatitis virus-related and bovine coronavirus-related coronaviruses has been suggested. The remarkably high genetic similarity among the bovine coronavirus-related coronaviruses indicates a relatively recent common evolutionary history. In this chapter, we discuss the molecular evolution of these closely related group 2 coronaviruses read more ...