Stop Codon Usage of Three Gene Families in Selected Medical Insects, and their Phylogenetic Relationships

Medical insects pose significant health risks, transmitting disease causing agents with significant morbidity and mortality globally. Understanding their genetic composition and evolutionary relationship is crucial to developing control techniques to combat them. This study aims to compare the stop codon usage of gustatory, odorant and kinase genes, and assess their use as markers for evaluating the phylogenetic relationship between selected medical insects. Fifteen genes from three gene families including gustatory receptors, odorant receptors, and kinases were studied in thirty-four insect species. Gene and transcript sequences were retrieved from Ensembl Metazoa database. The stop codon usage was obtained by identifying the stop codon present at the end of the transcript sequences. Multiple sequence alignment of the gene sequences was performed and phylogenetic trees were computed. There were variations in the stop codon usage across the different insect species. The odorant receptor and kinase genes grouped the insects into two major clusters. The stop codon usage highlighted the variation within and among the species. The phylogenetic analysis results supported existing insect classification. These approaches could be considered for phylogenetic analyses of other arthropod groups. Accurate measurement of stop codon usage will be important for understanding natural selection, the genetic variation of coding sequences of genes, and useful in design of more efficient expression constructs in gene-editing techniques for vector control.