SINGAPORE - Phylogenetic testing compares different virus genomes and helps scientists deduce the index case of a Covid-19 cluster.
In the case of the Jurong Fishery Port cluster, the authorities were able to determine that the strains relating to the cluster were of the Delta variant and similar to what was seen in imported cases from Indonesia.
Dr Sebastian Maurer-Stroh, executive director of the Bioinformatics Institute at A*Star, said a phylogenetic or "family" tree is created using viral mutations as markers to compare the virus genomes.
In this family tree, close relatives are grouped together and one can then see which cases had formed a cluster - in this way, one can then deduce the ancestor of a cluster, said Dr Maurer-Stroh.