Research Interests
I am interested in understanding the genetic basis of genome evolution. Here are some of the current projects in the lab.
(Click on titles for more information and recent publications.)
- Role of Mutational Origins on Genome Evolution
- Functional Genomics of Non-coding Sequences
- Determinants of Genome Evolution
- Molecular Evolution and Phylogenomics of New World Primates
Functional Genomics of Non-coding Sequences
Many vertebrate genomes (and other organisms) consist of a large amount of non-coding (not-protein-coding) nucleotides. For example, protein-coding regions occupy mere 2% of the human genome. The role of such vast amounts of non-coding sequences is an intriguing question. We use computational and experimental approaches to investigate this problem. Recently, we analyzed molecular evolution of novel, non-coding transcribed sequences (henceforth referred to as 'novel transcripts') in the human genome identified from a genome tiling microarray study (Leon et al. submitted). Our preliminary results indicate that novel transcripts are under purifying selection, and are functionally relevant. Interestingly, we also found that novel transcripts show significant avoidance of transposable element accumulation, and increased level of G and C nucleotides. These results highlight the yet unknown complexity of human transcriptome. Moreover, models of genome evolution need to consider the roles of unannotated, novel transcripts on genomic distribution of repetitive elements and evolution of nucleotide composition. We are interested in testing roles of different non-coding regulatory sequences on expression levels of nearby genes, using experimental approaches. In addition, we are currently undertaking a study of diversification of non-coding and coding functional RNAs following genome duplication.Leon, A., Elango, N. and Yi, S. (2007). Functionality of non-coding, intergenic transcripts in the human genome. submitted. (preprint available upon request)