Question

The phylogenetic tree shown was constructed using a nucleotide distance matrix of Ebola virus isolates from Guinea in March 2014 (“G”), Sierra Leone (“S”), and Mali (“M”) in October/November 2014. Describe what the phylogeny revealed regarding the three Ebola outbreaks.

G1 G2 G3 SL1 M2 M1 M3 M4 SL2 SL3 SL4 SL5

Answer 1

The phylogenetic tree shows that there are three different strains of Ebola virus. Three strains are G, SL and M. Each of the three strains has different serotypes ( due to mutation in the antigenic epitopes of the same strain of virus serotypes are generated).

The first outbreak of Ebola virus occured in March 2014 and the strain was SL. From SL 1 strain another serotype of SL, named SL2 was evolved and a new strain G was evolved. G strain was further evolved into three serotypes named G1, G2 and G3. From SL2 strain, a new strain was evolved named M. Another three serotypes were evolved from SL 2 named SL3, SL4 and SL5. From M strain, four serotypes were evolved named M1, M2, M3 and M4

The phylogenetic tree also tells us that G3 and SL1 strains are more closely related. SL3 and SL4 are more closely related to SL2 than SL5.