I am an interdisciplinary computational molecular biologist wishing to understand how mutation and selection shape things that are living or once lived. I joined University of Hong Kong in 1996, and served as Head of Bioinformatics Laboratory in the newly established HKU-Pasteur Research Centre in 2001. I came back to Canada in 2002 and am full professor at University of Ottawa. I am currently recruiting PhD and MSc students.Here are some of my research interests:Coevolution between signals and their decoders at the molecular level: Sense codons are decoded by tRNAs, stop codons by release factors, Shine-Delgarno (SD) sequences in bacterial mRNAs are decoded by the anti-SD sequences at the 3' end of the small subunit ribosomal RNA, splicing sites are decoded by spliceosomes, DNA replication origin signals are decoded by dnaA proteins in bacteria and ORC proteins in Archaea and Eukaryota, and so on. I have developed and used bioinformatic tools to extensively study the coevolution between these signals and their decoders.Phylogenetic and phylogeographic Methods and Models: I have developed novel methods for constructing phylogenetic trees (evolutionary trees) from molecular sequence data. My contributions include improving the accuracy of sequence alignment, tree-building algorithms, substitution model selection, and potential biases in phylogenetic methods. I wish to understand how biodiversity originated, evolved, migrated, colonized and come to be distributed on earth over time.Genome Evolution and Adaptation: I aim to understand how microbial genomes evolve in response to new environments (e.g., a new host or a new ecologicla niche) and how genes are gained, lost or modified during the adaptation process. I am particularly interested in host-pathogen coevolution.Software Development: I have written and maintained DAMBE (Data Analysis in Molecular Biology and Evolution) for the research community in molecular biology and evolution. I have also written and maintained several other programs. Please visit my lab page at http://dambe.bio.uottawa.ca.(Please email me at xxia@uottawa.ca if you want to connect. I ignore/delete linkedin notifications).