ABSTRACT
We analysed natural recombination in 79 Human enterovirus A strains representing 13 serotypes by sequencing of VP1, 2C and 3D genome regions. The half-life of a non-recombinant tree node in coxsackieviruses 2, 4 and 10 was only 3.5 years, and never more than 9 years. All coxsackieviruses that differed by more than 7â% of the nucleotide sequence in any genome region were recombinants relative to each other. Enterovirus 71 (EV71), on the contrary, displayed remarkable genetic stability. Three major EV71 clades were stable for 19-29 years, with a half-life of non-recombinant viruses between 13 and 18.5 years in different clades. Only five EV71 strains out of over 150 recently acquired non-structural genome regions from coxsackieviruses, while none of 80 contemporary coxsackieviruses had non-structural genes transferred from the three EV71 clades. In contrast to earlier observations, recombination between VP1 and 2C genome regions was not more frequent than between 2C and 3D regions.
Subject(s)
Enterovirus A, Human/genetics , Evolution, Molecular , Gene Pool , Recombination, Genetic , Genomic Instability , Humans , Molecular Sequence Data , RNA, Viral/genetics , Sequence Analysis, DNA , Viral Proteins/geneticsABSTRACT
The full coding sequences of two novel human enterovirus (HEV)-C serotypes 105 and 116, sampled in the Republic of the Congo in 2010 and in Russia in 2011, were identified in this study. Enterovirus (EV)-105 was closest to EV-104 in the 5' NTR and to EV-109 in the coding genome region. It had the same unconventional 5' NTR as EV-104 and EV-109. The non-cytopathogenic EV-116 was phylogenetically close to coxsackievirus (CV)-A1, CV-A19 and CV-A22, which also cannot be propagated in routinely used cell cultures. There were signs of recombination within this subgroup of HEV-C; however, recombination with conventional HEV-C was restricted, implying partial reproductive isolation. As there is also evidence of different permissive replication systems and distinct genetic properties of these subgroups, they may represent subspecies of the HEV-C species or different stages of speciation.
