Dr. Naomi Fast

Our research strives to understand genome evolution in single-celled eukaryotes, focusing on changes in genome size. As genomes are reduced in size, there are likely to be changes in the amounts of non-coding material. Of particular interest is the retention, reduction and/or removal of introns. Introns interrupt genes, and are removed from mRNA by a large macromolecular protein and RNA complex called the spliceosome. In metazoans, where genomes tend to be quite large, introns can be quite long (sometimes several kb), and the spliceosome is extremely large with over a hundred proteins. In contrast, the yeast Saccharomyces possesses a much smaller genome and has relatively few introns that tend to be short. The yeast spliceosome is also predicted to be smaller, with only ~80 proteins. A lineage of lesser-studied eukaryotes, the microsporidia, are distantly related to fungi and possess genomes that are very tiny; at the extreme, smaller than many bacterial genomes. Using microsporidia as a model system, we are examining the effects of genome reduction on the evolution of introns and the spliceosomal machinery.