Metagenomic analysis of integron gene cassettes: diversity and distribution of a mobile gene pool

In bacterial evolution Lateral Gene Transfer (LGT) is a form of illegitimate recombination that can occur between different species. It has been demonstrated that LGT can facilitate the transfer of many different genes including those that encode virulence factors and antibiotic resistance. The scope of this project is to examine one particular mechanism in bacteria that facilitates LGT - the integron. Integrons are best considered as genetic platforms that can promote LGT through autonomous acquisition, re-arrangement and expression of modified genetic determinants called gene cassettes. The majority of characterized gene cassettes determine antibiotic-resistance in pathogens and this system is the dominant force facilitating multi-drug resistance in bacteria; therefore, we are interested in obtaining a better understanding of this genetic element. The goals of this study are as follows: 1. Using environmental genomics, survey gene cassettes from human pathogens and micro flora using a non-biased approach. 2. Survey cassettes that are subjected to known selective pressures differing from antibiotics. 3. Generate an integron gene-cassette sequence database. 4. Analyze this data in terms of functional, biogeographical and phylogenetic distribution. 5. From the analysis, address questions pertaining to multi-drug resistance in pathogenic bacteria and additional instances of integron-facilitated adaptation such as metabolism of toxins that could present bioremediation approaches.