Role of Horizontal Gene Transfer Events in the Evolution of Phenol 2–Monooxygenase Gene: a Comparative Study across 75 Prokaryotic Genomes

Horizontal Gene Transfer (HGT) is a major evolutionary force with a significant role in microbial evolution. In the present study, we report an in silico evidence for HGT of Phenol 2–Monooxygenase Gene which is responsible for converting Phenol to Catechol and is the initial and rate–limiting step in phenol degradation. Five computational approaches were applied across 75 completely sequenced prokaryotic genomes for studying the prospects of horizontal gene transfer of Phenol 2–Monooxygenase Gene. The phylogenetic incongruencies between the species tree (based on 16S rRNA gene) and the gene tree (using Phenol 2–Monooxygenase Gene) supported by high bootstrap values, discrepancies in %GC content, %GC3 content, codon usage analysis based on Codon Adaptation Index (CAI) and effective Number of codons (Nc) led to the conclusion that Horizontal Gene Transfer events might have taken place during the evolution of this gene. Tree and Reticulogram Reconstruction (T–REX) was constructed that detected the HGT events with significant bootstrap values, further making HGT an evident event in the evolution of this gene.