In this work we analyze triplet entropy in a set of H1N1 virus sequences. We correlated measures of entropy and guanine and cytosine concentration with chronology sample for a set of more than 30,000 sequences. This description allowed us to draw a map of the virus organizational changes throughout the 20th century. The main conclusion of our analysis was to show that some virus segments are mutating with a higher rate than others over the years and, in some cases, they are clustering sequences into new subgroups. A higher changing rate was found precisely in PA and PB1 segments, which are parts of H1N1 replication machinery. This highlights that organizational measures, as presented here, partially reflect segment dynamics and corroborates some recent experimental findings, which showed that during the last virus outbreak there has been a major change in polymerase activity. This type of approach may help to optimize treatment targets for this disease.
H1N1; Entropy; DNA
