Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases
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Infect. Genet. Evol. · Mar 2006
Historical ArticleOn the phylogenetic placement of human T cell leukemia virus type 1 sequences associated with an Andean mummy.
Recently, the putative finding of ancient human T cell leukemia virus type 1 (HTLV-1) long terminal repeat (LTR) DNA sequences in association with a 1500-year-old Chilean mummy has stirred vigorous debate. The debate is based partly on the inherent uncertainties associated with phylogenetic reconstruction when only short sequences of closely related genotypes are available. However, a full analysis of what phylogenetic information is present in the mummy data has not previously been published, leaving open the question of what precisely is the range of admissible interpretation. ⋯ We then deduced possible phylogenetic positions for the two main categories of published Chilean mummy sequences, based on their published 157-nucleotide LTR sequences. The possible phylogenetic placements for one of the mummy sequence categories are consistent with a modern origin. However, one of these placements for the other mummy sequence category falls very close to the root of the Cosmopolitan clade, consistent with an ancient origin for both this mummy sequence and the Cosmopolitan clade.
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Infect. Genet. Evol. · Sep 2003
SARS associated coronavirus has a recombinant polymerase and coronaviruses have a history of host-shifting.
The sudden appearance and potential lethality of severe acute respiratory syndrome associated coronavirus (SARS-CoV) in humans has focused attention on understanding its origins. Here, we assess phylogenetic relationships for the SARS-CoV lineage as well as the history of host-species shifts for SARS-CoV and other coronaviruses. We used a Bayesian phylogenetic inference approach with sliding window analyses of three SARS-CoV proteins: RNA dependent RNA polymerase (RDRP), nucleocapsid (N) and spike (S). ⋯ However, current sampling suggests host-species shifts between mouse and rat, chicken and turkey, mammals and manx shearwater, and humans and other mammals. The sister relationship between avian coronaviruses and the 3' RDRP fragment of SARS-CoV suggests an additional host-species shift. Demonstration of recombination in the SARS-CoV lineage indicates its potential for rapid unpredictable change, a potentially important challenge for public health management and for drug and vaccine development.