In a recent paper in Science, surveyed the position of introns in 30 genes of a marine annelid and showed that over 60% of the introns occupy positions identical to those in human homologs. In contrast, both human and marine annelid genes share only 30% of their introns with other invertebrates. These observations suggest that the common ancestor of most animal phyla had intron-rich genes and reinforce the notion that introns proliferated early in the evolutionary history of eukaryotes.
Center for Evolutionary Functional Genomics, Biodesign Institute, and School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA. s.kumar@asu.edu
